Method and apparatus for transmitting control information in a wireless communication system

ABSTRACT

The present invention relates to a wireless communication system. More particularly, the present invention relates to a method for transmitting acknowledgement/negative ACK (ACK/NACK) in a wireless communication system which supports carrier aggregation, and to an apparatus for the method. A method in which a terminal transmits ACK/NACK in a wireless communication system that supports carrier aggregation comprises the following steps: receiving a physical downlink control channel (PDCCH); receiving a physical downlink shared channel (PDSCH) indicated by the PDCCH; and transmitting ACK/NACK for the PDSCH via a physical uplink control channel (PUCCH). A PUCCH format for transmitting ACK/NACK is selected by taking the number of aggregated carriers into account.

TECHNICAL FIELD

The present invention relates to a wireless communication system and,more particularly, to a method and apparatus for transmitting controlinformation. The wireless communication system can support carrieraggregation (CA).

BACKGROUND ART

Extensive research has been conducted to provide various types ofcommunication services including voice and data services in wirelesscommunication systems. In general, a wireless communication system is amultiple access system that supports communication with multiple usersby sharing available system resources (e.g. bandwidth, transmissionpower, etc.) among the multiple users. The multiple access system mayadopt a multiple access scheme such as Code Division Multiple Access(CDMA), Frequency Division Multiple Access (FDMA), Time DivisionMultiple Access (TDMA), Orthogonal Frequency Division Multiple Access(OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA),etc.

DISCLOSURE Technical Problem

An object of the present invention is to provide a method and apparatusfor efficiently transmitting control information in a wirelesscommunication system. Another object of the present invention is toprovide a channel format, signal processing method and apparatus forefficiently transmitting control information. Another object of thepresent invention is to provide a method and apparatus for efficientlyallocating resources for transmitting control information.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present invention are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present invention could achieve will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings.

Technical Solution

In an aspect of the present invention, there is provided a method for,at a user equipment (UE), transmitting ACK/NACK in a wirelesscommunication that supports carrier aggregation, the method including:receiving a physical downlink shared channel (PDCCH); receiving aphysical downlink shared channel (PDSCH) indicated by the PDCCH; andtransmitting ACK/NACK for the PDSCH through a physical uplink controlchannel (PUCCH), wherein the PUCCH format for transmitting the ACK/NACKis selected in consideration of the number of aggregated carriers.

In another aspect of the present invention, there is provided a UEconfigured to transmit ACK/NACK in a wireless communication system thatsupports carrier aggregation, the UE including: an RF unit; and aprocessor, the processor configured to receive a PDCCH, to receive aPDSCH indicated by the PDCCH, and to transmit the ACK/NACK for the PDSCHthrough a PUCCH, wherein the PUCCH format for transmitting the ACK/NACKis selected in consideration of the number of aggregated carriers.

The PUCCH format for transmitting the ACK/NACK is selected inconsideration of whether the number of aggregated carriers is 2 orgreater.

The ACK/NACK may be transmitted using a first PUCCH format if the numberof aggregated carriers is 1 and transmitted using a second PUCCH formatif the number of aggregated carriers is 2 or greater.

If the ACK/NACK is transmitted using the first PUCCH format, a sequencegenerated by a root sequence and a cyclic shift is used, and if theACK/NACK is transmitted using the second PUCCH format, discrete Fouriertransform (DFT) is used.

A resource for the first PUCCH format may be linked with an index of acontrol channel element (CCE) that constitutes the PDCCH, and a resourcefor the second PUCCH format may be indicated by the PDCCH.

Advantageous Effects

According to embodiments of the present invention, control informationcan be efficiently transmitted in a wireless communication system.Furthermore, a channel format and a signal processing method forefficiently transmitting control information can be provided. Inaddition, resources for control information transmission can beefficiently allocated.

It will be appreciated by persons skilled in the art that that theeffects that could be achieved with the present invention are notlimited to what has been particularly described hereinabove and otheradvantages of the present invention will be more clearly understood fromthe following detailed description taken in conjunction with theaccompanying drawings.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates physical channels used in a 3GPP LTE system and asignal transmission method using the same;

FIG. 2 illustrates an uplink signal processing procedure;

FIG. 3 illustrates a downlink signal processing procedure;

FIG. 4 illustrates SC-FDMA and OFDMA schemes;

FIGS. 5A and 5B illustrate a signal mapping scheme in a frequencydomain, which satisfies single carrier property;

FIG. 6 illustrates a signal processing procedure of mapping DFT processoutput samples to a single carrier in clustered SC-FDMA;

FIGS. 7 and 8 illustrate a signal processing procedure of mapping DFTprocess output samples to multiple carriers in clustered SC-FDMA;

FIG. 9 illustrates a signal processing procedure in segmented SC-FDMA;

FIG. 10 illustrates a signal processing procedure for transmittingreference signal (RS) on uplink;

FIG. 11 illustrates a subframe structure for transmitting RS in case ofnormal CP;

FIGS. 12A and 12B illustrate a subframe structure for transmitting RS incase of extended CP;

FIG. 13 illustrates PUCCH formats 1a and 1b in the case of normal CP;

FIG. 14 illustrates PUCCH formats 1a and 1b in the case of extended CP;

FIG. 15 illustrates a PUCCH structure at subframe level;

FIG. 16 illustrates ACK/NACK channelization for PUCCH formats 1a and 1b;

FIG. 17 illustrates channelization for a hybrid structure of PUCCHformats 1/1a/1b and 2/2a/2b in the same PRB;

FIG. 18 illustrates a slot level structure of PUCCH format 2/2a/2b;

FIG. 19 illustrates PRB allocation for PUCCH transmission;

FIG. 20 illustrates a concept of management of downlink componentcarriers in a base station (BS);

FIG. 21 illustrates a concept of management of uplink component carriersin a user equipment (UE);

FIG. 22 illustrates a concept of management of multiple carriers by oneMAC layer in a BS;

FIG. 23 illustrates a concept of management of multiple carriers by oneMAC layer in a UE;

FIG. 24 illustrates a concept of management of multiple carriers bymultiple MAC layers in a BS;

FIG. 25 illustrates a concept of management of multiple carriers bymultiple MAC layers in a UE;

FIG. 26 illustrates a concept of management of multiple carriers bymultiple MAC layers in a BS;

FIG. 27 illustrates a concept of management of multiple carriers by oneor more MAC layers in a UE;

FIG. 28 illustrates asymmetrical carrier aggregation in which aplurality of DL CCs is linked to one UL CC;

FIGS. 29A-29F and 30 illustrate a PUCCH format and a signal processingprocedure for the same according to an embodiment of the presentinvention;

FIGS. 31 to 34 illustrate a PUCCH format and a signal processingprocedure for the same according to another embodiment of the presentinvention;

FIGS. 35A and 35B illustrate PUCCH resources according to an embodimentof the present invention;

FIGS. 36A, 36B, 37A, 37B, 38A, 38B, 39A, 39B, 40A, 40B and 41 illustratePUCCH resources according to an embodiment of the present invention;

FIGS. 42A to 42F illustrate PUCCH resources according to an embodimentof the present invention;

FIGS. 43A to 43C illustrate a signal processing procedure fortransmitting a PUCCH through multiple antennas according to anembodiment of the present invention;

FIG. 44 illustrates a PUCCH format and a signal processing procedure forthe same according to another embodiment of the present invention;

FIG. 45 illustrates PUCCH format adaptation and a blind decodingprocedure of a BS in a carrier aggregation system;

FIGS. 46, 47 and 48 illustrate PUCCH format adaptation according to anembodiment of the present invention;

FIGS. 49, 50 and 51 show a UCI bit length and a block error rateaccording to PUCCH format;

FIGS. 52 to 63 illustrate PUCCH resource allocation according to anotherembodiment of the present invention; and

FIG. 64 illustrates configurations of a BS and a UE applicable to thepresent invention.

BEST MODE

Embodiments of the present invention are applicable to a variety ofwireless access technologies such as Code Division Multiple Access(CDMA), Frequency Division Multiple Access (FDMA), Time DivisionMultiple Access (TDMA), Orthogonal Frequency Division Multiple Access(OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA),etc. CDMA can be implemented as a wireless technology such as UniversalTerrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented asa wireless technology such as Global System for Mobile communications(GSM)/General Packet Radio Service (GPRS)/Enhanced Data Rates for GSMEvolution (EDGE). OFDMA can be implemented as a wireless technology suchas Institute of Electrical and Electronics Engineers (IEEE) 802.11(Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwide interoperability forMicrowave Access (WiMAX)), IEEE 802.20, Evolved UTRA (E-UTRA). UTRA is apart of Universal Mobile Telecommunications System (UMTS). 3^(rd)Generation Partnership Project (3GPP) Long Term Evolution (LTE) is apart of Evolved UMTS (E-UMTS) using E-UTRA. LTE-Advanced (LTE-A) is anevolution of 3GPP LTE. While the following description is given,centering on 3GPP LTE/LTE-A for clarity of description, this is purelyexemplary and thus should not be construed as limiting the presentinvention.

In a wireless communication system, a UE receives information from a BSthrough downlink and transmits information to the BS through uplink.Information transmitted and received between the BS and the UE includesdata and various types of control information. Various physical channelsare present according to type/usage of information transmitted andreceived between the BS and the UE.

FIG. 1 illustrates physical channels used in a 3GPP LTE system and asignal transmission method using the same.

When powered on or when a UE initially enters a cell, the UE performsinitial cell search involving synchronization with a BS in step S101.For initial cell search, the UE may be synchronized with the BS andacquire information such as a cell Identifier (ID) by receiving aPrimary Synchronization Channel (P-SCH) and a Secondary SynchronizationChannel (S-SCH) from the BS. Then the UE may receive broadcastinformation from the cell on a Physical Broadcast Channel (PBCH). In themean time, the UE may determine a downlink channel status by receiving aDownlink Reference Signal (DL RS) during initial cell search.

After initial cell search, the UE may acquire more specific systeminformation by receiving a Physical Downlink Control Channel (PDCCH) andreceiving a Physical Downlink Shared Channel (PDSCH) based oninformation of the PDCCH in step S102.

The UE may perform a random access procedure to access the BS in stepsS103 to S106. For random access, the UE may transmit a preamble to theBS on a Physical Random Access Channel (PRACH) (S103) and receive aresponse message for preamble on a PDCCH and a PDSCH corresponding tothe PDCCH (S104). In the case of contention-based random access, the UEmay perform a contention resolution procedure by further transmittingthe PRACH (S105) and receiving a PDCCH and a PDSCH corresponding to thePDCCH (S106).

After the foregoing procedure, the UE may receive a PDCCH/PDSCH (S107)and transmit a Physical Uplink Shared Channel (PUSCH)/Physical UplinkControl Channel (PUCCH) (S108), as a general downlink/uplink signaltransmission procedure. Here, control information transmitted from theUE to the BS is called uplink control information (UCI). The UCI mayinclude a Hybrid Automatic Repeat and requestAcknowledgement/Negative-ACK (HARQ ACK/NACK) signal, scheduling request(SR), a Channel Quality Indicator (CQI), a Precoding Matrix Index (PMI),a Rank Indication (RI), etc. While the UCI is transmitted through aPUCCH in general, it may be transmitted through a PUSCH when controlinformation and traffic data need to be simultaneously transmitted. TheUCI may be aperiodically transmitted through a PUSCH at therequest/instruction of a network.

FIG. 2 illustrates a signal processing procedure through which a UEtransmits an uplink signal.

To transmit the uplink signal, a scrambling module 210 of the UE mayscramble the uplink signal using a UE-specific scramble signal. Thescrambled signal is input to a modulation mapper 220 in which thescrambled signal is modulated into complex symbols using Binary PhaseShift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) or16-Quadrature amplitude Modulation (QAM)/64-QAM according to signal typeand/or channel status. The modulated complex symbols are processed by atransform precoder 230, and then applied to a resource element mapper240. The resource element mapper 240 may map the complex symbols totime-frequency resource elements. The signal processed in this mannermay be subjected to an SC-FDMA signal generator 250 and transmitted to aBS through an antenna.

FIG. 3 illustrates a signal processing procedure through which the BStransmits a downlink signal.

In a 3GPP LTE system, the BS may transmit one or more codewords ondownlink. The codewords may be processed into complex symbols through ascrambling module 301 and a modulation mapper 302 as in the uplink shownin FIG. 2. Then, the complex symbols are mapped to a plurality of layersby a layer mapper 303. The layers may be multiplied by a precodingmatrix in a precoding module 304 and allocated to transport antennas.The processed signals for the respective antennas may be mapped totime-frequency resource elements by a resource element mapper 305 andsubjected to an OFDM signal generator 306 to be transmitted through theantennas.

When the UE transmits an uplink signal in a wireless communicationsystem, a peak-to-average ratio (PAPR) becomes a problem, as compared toa case in which the BS transmits a downlink signal. Accordingly, uplinksignal transmission uses SC-FDMA while downlink signal transmission usesOFDMA, as described above with reference to FIGS. 2 and 3.

FIG. 4 illustrates SC-FDMA and OFDMA schemes. The 3GPP system employsOFDMA in downlink and uses SC-FDMA in uplink.

Referring to FIG. 4, both a UE for transmitting an uplink signal and aBS for transmitting a downlink signal include a serial-to-parallelconverter 401, a subcarrier mapper 403, an M-point IDFT module 404, anda cyclic prefix (CP) adder 406. The UE for transmitting a signalaccording to SC-FDMA additionally includes an N-point DFT module 402.

FIG. 5 illustrates a signal mapping scheme in a frequency domain, whichsatisfies single carrier property. FIG. 5(a) illustrates a localizedmapping scheme and FIG. 5B illustrates a distributed mapping scheme.

Clustered SC-FDMA, which is a modified version of SC-FDMA, will now bedescribed. Clustered SC-FDMA divides DFT process output samples intosub-groups in a subcarrier mapping process and discretely maps thesub-groups to the frequency domain (or subcarrier domain).

FIG. 6 illustrates a signal processing procedure for mapping DFT processoutput samples to a single carrier in clustered SC-FDMA. FIGS. 7 and 8illustrate a signal processing procedure for mapping DFT process outputsamples to multiple carriers in clustered SC-FDMA. FIG. 6 shows anexample of application of intra-carrier clustered SC-FDMA while FIGS. 7and 8 show examples of application of inter-carrier clustered SC-FDMA.FIG. 7 illustrates a case in which a signal is generated through asingle IFFT block when subcarrier spacing between neighboring componentcarriers is set while component carriers are contiguously allocated inthe frequency domain. FIG. 8 shows a case in which a signal is generatedthrough a plurality of IFFT blocks when component carriers arenon-contiguously allocated in the frequency domain.

FIG. 9 illustrates a signal processing procedure in segmented SC-FDMA.

Segmented SC-FDMA is a simple extension of the DFT spreading and IFFTsubcarrier mapping structure of the conventional SC-FDMA, when thenumber of DFT blocks is equal to the number of IFFT blocks and thus theDFT blocks and the IFFT blocks are in one-to-one correspondence. Whilethe term ‘segmented SC-FDMA’ is adopted herein, it may also be calledNxSC-FDMA or NxDFT spread OFDMA (NxDFT-s-OFDMA). Referring to FIG. 9,the segmented SC-FDMA is characterized in that total time-domainmodulation symbols are divided into N groups (N is an integer largerthan 1) and a DFT process is performed on a group-by-group basis torelieve the single carrier property constraint.

FIG. 10 illustrates an uplink subframe structure.

Referring to FIG. 10, an uplink subframe includes a plurality of slots(e.g. two slots). The slots may include different numbers of SC-FDMAsymbols according to CP length. For example, the slot can include 7SC-FDMA symbols in case of normal CP. The uplink subframe is dividedinto a data region and a control region. The data region includes aPUSCH and is used to transmit a data signal such as audio data. Thecontrol region includes a PUCCH and is used to transmit UCI. The PUCCHincludes RB pairs (e.g. 7 RB pairs in frequency mirrored positions, andm=0, 1, 2, 3, 4) located on both ends of the data region in thefrequency domain and is hopped based on slots. The UCI includes HARQACK/NACK, CQI, PMI, RI, etc.

FIG. 11 illustrates a signal processing procedure for transmitting areference signal (RS) on uplink. While data is converted into afrequency domain signal through a DFT precoder, frequency-mapped, andthen transmitted through IFFT, an RS does not passes the DFT precoder.Specifically, an RS sequence generated in the frequency domain (S11) issequentially subjected to localization mapping (S12), IFFT (S13) and CPaddition (S14) to be transmitted.

RS sequence r_(u,ν) ^((α))(n) is defined by cyclic shift α of a basesequence and may be represented by Equation 1.

r _(u,ν) ^((α))(n)=e ^(jαn) r _(u,ν)(n), 0≦n<M _(sc) ^(RS)   [Equation1]

Here, M_(sc) ^(RS)=mN_(sc) ^(RB) denotes the length of the RS sequence,N_(sc) ^(RB) denotes a resource block size on a subcarrier basis,1≦m≦N_(RB) ^(mac,UL), and N_(RB) ^(max,UL) represents a maximum uplinktransmsision bandwidth.

Base sequence r _(u,ν)(n) is divided into several groups. u ε {0,1, . .. , 29} denotes a group number and ν corresponds to a base sequencenumber in a corresponding group. Each group inculdes one base sequence(ν=0) having a length of M_(sc) ^(RS)=mN_(sc) ^(RB) (1≦m≦5) and two basesequences (ν=0,1) having a length of M_(sc) ^(RS)=mN_(sc) ^(RB)(6≦m≦N_(RB) ^(max,UL)). The sequence group number u and base sequencenumber ν in the corresponding group may vary with time. Base sequence r_(u,ν)(0), . . . , r _(u,ν)(M_(sc) ^(RB)−1) is defined according tosequence length M_(sc) ^(RS).

A base sequence having a length of longer than 3N_(sc) ^(RB) can bedefined as follows.

For M_(sc) ^(RS)≧3N_(sc) ^(RB), base sequence r _(u,ν)(0), . . . , r_(u,ν)(M_(sc) ^(RB)−1) is given by the following Equation 2.

r _(u,ν)(n)=x _(q)(n mod N _(ZC) ^(RS)), 0≦n<M _(sc) ^(RS)   [Equation2]

Here, the q-th root Zadoff-Chu sequence can be defined by the followingEquation 3.

$\begin{matrix}{{{x_{q}(m)} = e^{{- j}\frac{\pi \; {{qm}{({m + 1})}}}{N_{ZC}^{RS}}}},{0 \leq m \leq {N_{ZC}^{RS} - 1}}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

Here, q satisifes the following Equation 4.

q=└q+1/2┘+ν·(−1)^(└2q┘)

q=N _(ZC) ^(RS)·(u+1)/31   [Equation 4]

The length N_(ZC) ^(RS) of the Zadoff-Chue sequence is given by thelargest prime number, and thus N_(ZC) ^(RS)<M_(sc) ^(RS) is satisfied.

A base sequence having a length of less than 3N_(sc) ^(RB) can bedefined as follows. The base sequence is given by the following Equation5 for M_(sc) ^(RS)=N_(sc) ^(RB) and M_(sc) ^(RB)=2N_(sc) ^(RB).

r _(u,ν)(n)=e ^(jφ(n)n/4), 0≦n≦M _(sc) ^(RS)−1   [Equation 5]

Here, for M_(sc) ^(RS)=N_(sc) ^(RB) and M_(sc) ^(RS)=2N_(sc) ^(RB), φ(n)is given as shown in Tables 1 and 2, respectively.

TABLE 1 u φ(0), . . . , φ(11) 0 −1 1 3 −3 3 3 1 1 3 1 −3 3 1 1 1 3 3 3−1 1 −3 −3 1 −3 3 2 1 1 −3 −3 −3 −1 −3 −3 1 −3 1 −1 3 −1 1 1 1 1 −1 −3−3 1 −3 3 −1 4 −1 3 1 −1 1 −1 −3 −1 1 −1 1 3 5 1 −3 3 −1 −1 1 1 −1 −1 3−3 1 6 −1 3 −3 −3 −3 3 1 −1 3 3 −3 1 7 −3 −1 −1 −1 1 −3 3 −1 1 −3 3 1 81 −3 3 1 −1 −1 −1 1 1 3 −1 1 9 1 −3 −1 3 3 −1 −3 1 1 1 1 1 10 −1 3 −1 11 −3 −3 −1 −3 −3 3 −1 11 3 1 −1 −1 3 3 −3 1 3 1 3 3 12 1 −3 1 1 −3 1 1 1−3 −3 −3 1 13 3 3 −3 3 −3 1 1 3 −1 −3 3 3 14 −3 1 −1 −3 −1 3 1 3 3 3 −11 15 3 −1 1 −3 −1 −1 1 1 3 1 −1 −3 16 1 3 1 −1 1 3 3 3 −1 −1 3 −1 17 −31 1 3 −3 3 −3 −3 3 1 3 −1 18 −3 3 1 1 −3 1 −3 −3 −1 −1 1 −3 19 −1 3 1 31 −1 −1 3 −3 −1 −3 −1 20 −1 −3 1 1 1 1 3 1 −1 1 −3 −1 21 −1 3 −1 1 −3 −3−3 −3 −3 1 −1 −3 22 1 1 −3 −3 −3 −3 −1 3 −3 1 −3 3 23 1 1 −1 −3 −1 −3 1−1 1 3 −1 1 24 1 1 3 1 3 3 −1 1 −1 −3 −3 1 25 1 −3 3 3 1 3 3 1 −3 −1 −13 26 1 3 −3 −3 3 −3 1 −1 −1 3 −1 −3 27 −3 −1 −3 −1 −3 3 1 −1 1 3 −3 −328 −1 3 −3 3 −1 3 3 −3 3 3 −1 −1 29 3 −3 −3 −1 −1 −3 −1 3 −3 3 1 −1

TABLE 2 u φ(0), . . . , φ(23) 0 −1 3 1 −3 3 −1 1 3 −3 3 1 3 −3 3 1 1 −11 3 −3 3 −3 −1 −3 1 −3 3 −3 −3 −3 1 −3 −3 3 −1 1 1 1 3 1 −1 3 −3 −3 1 31 1 −3 2 3 −1 3 3 1 1 −3 3 3 3 3 1 −1 3 −1 1 1 −1 −3 −1 −1 1 3 3 3 −1 −31 1 3 −3 1 1 −3 −1 −1 1 3 1 3 1 −1 3 1 1 −3 −1 −3 −1 4 −1 −1 −1 −3 −3 −11 1 3 3 −1 3 −1 1 −1 −3 1 −1 −3 −3 1 −3 −1 −1 5 −3 1 1 3 −1 1 3 1 −3 1−3 1 1 −1 −1 3 −1 −3 3 −3 −3 −3 1 1 6 1 1 −1 −1 3 −3 −3 3 −3 1 −1 −1 1−1 1 1 −1 −3 −1 1 −1 3 −1 −3 7 −3 3 3 −1 −1 −3 −1 3 1 3 1 3 1 1 −1 3 1−1 1 3 −3 −1 −1 1 8 −3 1 3 −3 1 −1 −3 3 −3 3 −1 −1 −1 −1 1 −3 −3 −3 1 −3−3 −3 1 −3 9 1 1 −3 3 3 −1 −3 −1 3 −3 3 3 3 −1 1 1 −3 1 −1 1 1 −3 1 1 10−1 1 −3 −3 3 −1 3 −1 −1 −3 −3 −3 −1 −3 −3 1 −1 1 3 3 −1 1 −1 3 11 1 3 3−3 −3 1 3 1 −1 −3 −3 −3 3 3 −3 3 3 −1 −3 3 −1 1 −3 1 12 1 3 3 1 1 1 −1−1 1 −3 3 −1 1 1 −3 3 3 −1 −3 3 −3 −1 −3 −1 13 3 −1 −1 −1 −1 −3 −1 3 3 1−1 1 3 3 3 −1 1 1 −3 1 3 −1 −3 3 14 −3 −3 3 1 3 1 −3 3 1 3 1 1 3 3 −1 −1−3 1 −3 −1 3 1 1 3 15 −1 −1 1 −3 1 3 −3 1 −1 −3 −1 3 1 3 1 −1 −3 −3 −1−1 −3 −3 −3 −1 16 −1 −3 3 −1 −1 −1 −1 1 1 −3 3 1 3 3 1 −1 1 −3 1 −3 1 1−3 −1 17 1 3 −1 3 3 −1 −3 1 −1 −3 3 3 3 −1 1 1 3 −1 −3 −1 3 −1 −1 −1 181 1 1 1 1 −1 3 −1 −3 1 1 3 −3 1 −3 −1 1 1 −3 −3 3 1 1 −3 19 1 3 3 1 −1−3 3 −1 3 3 3 −3 1 −1 1 −1 −3 −1 1 3 −1 3 −3 −3 20 −1 −3 3 −3 −3 −3 −1−1 −3 −1 −3 3 1 3 −3 −1 3 −1 1 −1 3 −3 1 −1 21 −3 −3 1 1 −1 1 −1 1 −1 31 −3 −1 1 −1 1 −1 −1 3 3 −3 −1 1 −3 22 −3 −1 −3 3 1 −1 −3 −1 −3 −3 3 −33 −3 −1 1 3 1 −3 1 3 3 −1 −3 23 −1 −1 −1 −1 3 3 3 1 3 3 −3 1 3 −1 3 −1 33 −3 3 1 −1 3 3 24 1 −1 3 3 −1 −3 3 −3 −1 −1 3 −1 3 −1 −1 1 1 1 1 −1 −1−3 −1 3 25 1 −1 1 −1 3 −1 3 1 1 −1 −1 −3 1 1 −3 1 3 −3 1 1 −3 −3 −1 −126 −3 −1 1 3 1 1 −3 −1 −1 −3 3 −3 3 1 −3 3 −3 1 −1 1 −3 1 1 1 27 −1 −3 33 1 1 3 −1 −3 −1 −1 −1 3 1 −3 −3 −1 3 −3 −1 −3 −1 −3 −1 28 −1 −3 −1 −1 1−3 −1 −1 1 −1 −3 1 1 −3 1 −3 −3 3 1 1 −1 3 −1 −1 29 1 1 −1 −1 −3 −1 3 −13 −1 1 3 1 −1 3 1 3 −3 −3 1 −1 −1 1 3

RS hopping will now be described.

The sequence group number u in slot n_(s) can be defined by grouphopping pattern f_(gh)(n_(s)) and a sequence-shift pattern f_(ss)according to Equation 6.

u=(f _(gh)(n _(s))+f _(ss))mod30   [Equation 6]

Here, mod denotes a modulo operation.

There are 17 different hopping patterns and 30 different sequence-shiftpatterns. Sequence group hopping may be enabled or disabled by means ofa parameter that enables group hopping and is provided by higher layers.

PUCCH and PUSCH have the same hopping pattern but may have differentsequence-shift patterns.

The group hopping pattern f_(gh)(n_(s)) is the same for PUSCH and PUCCHand given by the following Equation 7.

$\begin{matrix}{{f_{gh}\left( n_{s} \right)} = \left\{ \begin{matrix}0 & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {disabled}} \\{\left( {\sum\limits_{i = 0}^{7}\; {{c\left( {{8n_{s}} + i} \right)} \cdot 2^{i}}} \right){mod}\; 30} & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {enabled}}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

Here, c(i) corresponds to a pseudo-random sequence and the pseudo-randomsequence generator may be initialized with

$c_{init} = \left\lfloor \frac{N_{ID}^{cell}}{30} \right\rfloor$

at the beginning of each radio frame.

Sequence-shift pattern f_(ss) differs between PUCCH and PUSCH.

For PUCCH, sequence-shift pattern f_(ss) ^(PUCCH) is given by f_(ss)^(PUCCH)=N_(ID) ^(cell) mod30. For PUSCH, sequence shift pattern f_(ss)^(PUSCH) is given by f_(ss) ^(PUSCH)=(f_(ss) ^(PUCCH)+Δ_(ss))mod30.Δ_(ss) ε {0,1, . . . , 29} is configured by higher layers.

Sequence hopping will now be described.

Sequence hopping only applies for reference signals of length M_(sc)^(RS)≧6N_(sc) ^(RB).

For reference signals of length M_(sc) ^(RB)<6N_(sc) ^(RB), the basesequence number ν within the base sequence group is given by ν=0.

For reference signals of length M_(sc) ^(RS)≧6N_(sc) ^(RB), the basesequence number ν within the base sequence group in slot n_(s) is givenby the following Equation 8.

$\begin{matrix}{v = \left\{ \begin{matrix}{c\left( n_{s} \right)} & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {disabled}\mspace{14mu} {and}\mspace{14mu} {sequence}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {enabled}} \\0 & {otherwise}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

Here, c(t) corresponds to the pseudo-random sequence and a parameterthat is provided by higher layers and enables sequence hoppingdetermines if sequence hopping is enabled or not. The pseudo-randomsequence generator may be initialized with

$c_{init} = {{\left\lfloor \frac{N_{ID}^{cell}}{30} \right\rfloor \cdot 2^{5}} + f_{ss}^{PUSCH}}$

at the beginning of each radio frame.

A reference signal for PUSCH is determined as follows.

Reference signal sequence r^(PUSCH)(·) for PUSCH is defined byr^(PUSCH)(m·M_(sc) ^(RB)+n)=r_(u,ν) ^((α))(n) where

m = 0, 1 n = 0, …  , M_(sc)^(RS) − 1

and M_(sc) ^(RS)=M_(sc) ^(PUSCH).

A cyclic shift is given by α=2·^(n) ^(cs) /12 and n_(cs)=(n_(DMRS)⁽¹⁾+n_(DMRS) ⁽²⁾+n_(PRS)(n₂))mod12 in one slot.

Here, n_(DMRS) ⁽¹⁾ is a broadcast value, n_(DMRS) ⁽²⁾ is given by uplinkscheduling allocation, and n_(PRS)(n_(s)) is a cell-specific cyclicshift value. n_(PRS)(n_(s)) varies with slot number n_(s) and is givenby n_(PRS)(n_(s))=Σ_(i=0) ⁷c(8·n_(s)+u)·2^(i).

Here, c(i) denotes the psedo-random sequence and is a cell-specificvalue. The psedo-random sequence generator may be initialized with

$c_{init} = {{\left\lfloor \frac{N_{ID}^{cell}}{30} \right\rfloor \cdot 2^{5}} + f_{ss}^{PUSCH}}$

at the beginning of each radio frame.

Table 3 shows a cyclic shift field and n_(DMRS) ⁽²⁾ in downlink controlinformation (DCI) format 0.

TABLE 3 Cyclic shift field at DCI format 0 n_(DMRS) ⁽²⁾ 000 0 001 2 0103 011 4 100 6 101 8 110 9 111 10

A physical mapping method for an uplink RS in a PUSCH will now bedescribed.

The sequence is multiplied with the amplitude scaling factor β_(PUSCH)and mapped to the same set of a physical resource block (PRB) used forthe corresponding PUSCH in a sequence starting with r^(PUSCH)(0).Mapping to resource elements (k, l), with l=3 for normal CP and l=2 forextended CP, in the subframe will be in increasing order of first k,then the slot number.

In summary, a ZC sequence is used with cyclic extension for length3N_(sc) ^(RB) or larger, whereas a computer generated sequence is usedfor length less than 3N_(sc) ^(RB). A cyclic shift is determinedaccording to cell-specific cyclic shift, UE-specific cyclic shift andhopping pattern.

FIG. 12a shows a DMRS structure for PUSCH in case of normal CP and FIG.12b shows a DMRS structure for PUSCH in case of extended CP. A DMRS istransmitted through the fourth and eleventh SC-FDMA symbols in FIG. 12aand transmitted through the third and ninth SC-FDMA symbols in FIG. 12b.

FIGS. 13 to 16 illustrate slot level structures of PUCCH formats. APUCCH has the following formats in order to transmit controlinformation.

(1) Format 1: on-off keying (OOK) modulation, used for schedulingrequest (SR).

(2) Formats 1a and 1b: used for ACK/NACK transmission.

1) Format 1a: BPSK ACK/NACK for one codeword

2) Format 1b: QPSK ACK/NACK for two codewords

(3) Format 2: QPSK modulation, used for CQI transmission.

(4) Formats 2a and 2b: used for simultaneous transmission of CQI andACK/NACK

Table 4 shows modulation schemes according to PUCCH format and thenumber of bits per subframe. Table 5 shows the number of RSs per slotaccording to PUCCH format and Table 6 shows SC-FDMA symbol position inan RS according to PUCCH format. In Table 4, PUCCH formats 2a and 2bcorrespond to normal CP.

TABLE 4 PUCCH Number of bits per format Modulation scheme subframe(M_(bit)) 1  N/A N/A 1a BPSK 1 1b QPSK 2 2  QPSK 20 2a QPSK + BPSK 21 2bQPSK + BPSK 22

TABLE 5 PUCCH format Normal CP Extended CP 1, 1a, 1b 3 2 2 2 1 2a, 2b 2N/A

TABLE 6 PUCCH SC-FDMA symbol position in RS format Normal CP Extended CP1, 1a, 1b 2, 3, 4 2, 3 2, 2a, 2b 1, 5 3

FIG. 13 illustrates PUCCH formats 1a and 1b in case of normal CP andFIG. 14 illustrates PUCCH formats 1a and 1b in case of extended CP. InPUCCH formats 1a and 1b, the same control information is repeated in asubframe on a slot-by-slot basis. ACK/NACK signals are respectivelytransmitted from UEs through different resources configured by differentcyclic shifts (CSs) (frequency domain codes) and orthogonal cover codes(OCs or OCCs) (time domain spreading codes) of a computer-generatedconstant amplitude zero auto correlation (CG-CAZAC) sequence. An OCincludes a Walsh/DFT orthogonal code, for example. If the number of CSsis 6 and the number of OCs is 3, a total of 18 UEs can be multiplexed inthe same physical resource block (PRB) on a single antenna basis.Orthogonal sequences w0,w1,w2,w3 may be applied in the arbitrary timedomain (after FFT modulation) or in the arbitrary frequency domain(prior to FFT modulation).

An ACK/NACK resource composed of CS, OC and PRB may be given to a UEthrough radio resource control (RRC) for SR and persistent scheduling.The ACK/NACK resource may be implicitly provided to the UE by the lowestCCE index of a PUCCH corresponding to a PDSCH for dynamic ACK/NACK andnon-persistent scheduling.

FIG. 15 illustrates PUCCH formats 2/2a/2b in case of normal CP and FIG.16 illustrates PUCCH formats 2/2a/2b in case of extended CP. Referringto FIGS. 15 and 16, one subframe includes 10 QPSK data symbols inaddition to RS symbols in case of normal CP. Each of the QPSK symbols isspread in the frequency domain by CS and then mapped to thecorresponding SC-FDMA symbol. SC-FDMA symbol level CS hopping may beapplied to randomize inter-cell interference. An RS may be multiplexedby CDM using CSs. For example, if the number of available CSs is 12 or6, 12 or 6 UEs can be multiplexed in the same PRB. That is, a pluralityof UEs can be multiplexed by CS+OC+PRB and CS+PRB in PUCCH formats1/1a/1b and 2/2a/2b respectively.

Orthogonal sequences with length-4 and length-3 for PUCCH formats1/1a/1b are shown in Table 7 and Table 8.

TABLE 7 Length-4 orthogonal sequences for PUCCH formats 1/1a/1b Sequenceindex Orthogonal sequences n_(oc) (n_(s)) [w(0) . . . w(N_(SF) ^(PUCCH)−1] 0 [+1 +1 +1 +1] 1 [+1 −1 +1 −1] 2 [+1 −1 −1 +1]

TABLE 8 Length-3 orthogonal sequences for PUCCH formats 1/1a/1b Sequenceindex Orthogonal sequences n_(oc) (n_(s)) [w(0) . . . w(N_(SF) ^(PUCCH)− 1)] 0 [1 1 1] 1 [1 e^(j2π/3) e^(j4π/3)] 2 [1 e^(j4π/3) e^(j2π/3)]

Orthogonal sequences for RS in PUCCH formats 1/1a/1b are shown in Table9.

TABLE 9 1a and 1b Sequence index n _(oc) (n_(s)) Normal cyclic prefixExtended cyclic prefix 0 [1 1 1] [1 1] 1 [1 e^(j2π/3) e^(j4π/3)] [1 −1]2 [1 e^(j4π/3) e^(j2π/3)] N/A

FIG. 17 illustrates ACK/NACK channelization for PUCCH formats 1a and 1b.FIG. 17 corresponds to a case of Δ_(shift) ^(PUCCH)=2.

FIG. 18 illustrates channelization for a hybrid structure of PUCCHformats 1/1a/1b and 2/2a/2b in the same PRB.

CS hopping and OC remapping may be applied as follows.

(1) Symbol-based cell-specific CS hopping for randomization ofinter-cell interference

(2) Slot level CS/OC remapping

1) For inter-cell interference randomization

2) Slot-based access for mapping between ACK/NACK channels and resources(k)

Resource n_(r) for PUCCH formats 1/1a/1b includes the followingcombination.

(1) CS (corresponding to a DFT orthogonal code at a symbol level) n_(cs)

(2) OC (orthogonal code at a slot level) n_(oc)

(3) Frequency resource block (RB) n_(rb)

A representative index n_(r) includes n_(cs), n_(oc) and n_(rb), whereindexes indicating CS, OC and RB are n_(cs), n_(oc), and n_(rb),respectively. Here, n_(r) satisfies n_(r)=(n_(cs), n_(oc), n_(rb))

CQI, PMI, RI and a combination of CQI and ACK/NACK may be transmittedthrough PUCCH formats 2/2a/2b. In this case, Reed-Muller (RM) channelcoding is applicable.

For example, channel coding for a UL CQI in an LTE system is describedas follows. Bit stream is a₀,a₁,a₂,a₃, . . . , a_(A−1) is channel-codedusing RM code (20,A). Table 10 shows a base sequence for code (20,A).Here, a₀ and a_(A−1) denote the most significant bit (MSB) and the leastsignificant bit (LSB). In the case of extended CP, a maximum number ofinformation bits is 11 in cases other than a case in which CQI andACK/NACK are simultaneously transmitted. The UL CQI may be subjected toQPSK modulation after being coded into 20 bits using the RM code. Thecoded bits may be scrambled before being subjcted to QPSK modulation.

TABLE 10 I M_(i, 0) M_(i, 1) M_(i, 2) M_(i, 3) M_(i, 4) M_(i, 5)M_(i, 6) M_(i, 7) M_(i, 8) M_(i, 9) M_(i, 10) M_(i, 11) M_(i, 12) 0 1 10 0 0 0 0 0 0 0 1 1 0 1 1 1 1 0 0 0 0 0 0 1 1 1 0 2 1 0 0 1 0 0 1 0 1 11 1 1 3 1 0 1 1 0 0 0 0 1 0 1 1 1 4 1 1 1 1 0 0 0 1 0 0 1 1 1 5 1 1 0 01 0 1 1 1 0 1 1 1 6 1 0 1 0 1 0 1 0 1 1 1 1 1 7 1 0 0 1 1 0 0 1 1 0 1 11 8 1 1 0 1 1 0 0 1 0 1 1 1 1 9 1 0 1 1 1 0 1 0 0 1 1 1 1 10 1 0 1 0 0 11 1 0 1 1 1 1 11 1 1 1 0 0 1 1 0 1 0 1 1 1 12 1 0 0 1 0 1 0 1 1 1 1 1 113 1 1 0 1 0 1 0 1 0 1 1 1 1 14 1 0 0 0 1 1 0 1 0 0 1 0 1 15 1 1 0 0 1 11 1 0 1 1 0 1 16 1 1 1 0 1 1 1 0 0 1 0 1 1 17 1 0 0 1 1 1 0 0 1 0 0 1 118 1 1 0 1 1 1 1 1 0 0 0 0 0 19 1 0 0 0 0 1 1 0 0 0 0 0 0

Channel-coded bits b₀,b₁,b₂,b₃, . . . , b_(B−1) may be generatedaccording to Equation 9.

$\begin{matrix}{b_{i} = {\sum\limits_{n = 0}^{A - 1}\; {\left( {a_{n} \cdot M_{i,n}} \right){mod}\; 2}}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

Here, i=0, 1, 2, . . . , B−1.

Table 11 shows an uplink control information (UCI) field for wideband(single antenna port, transmit diversity or open loop spatialmultiplexing PDSCH) CQI feedback.

TABLE 11 Field Band Wideband CQI 4

Table 12 shows a UCI field for wideband CQI and PMI feedback. This fieldreports closed loop spatial multiplexing PDSCH transmission.

TABLE 12 Band 2 antenna ports 4 antenna ports Field Rank = 1 Rank = 2Rank = 1 Rank > 1 Wideband CQI 4 4 4 4 Spatial differential CQI 0 3 0 3PMI (Precoding Matrix 2 1 4 4 Index)

Table 13 shows a UCI field for RI feedback for wideband report.

TABLE 13 Bit widths 4 antenna ports 2 antenna Maximum Maximum Fieldports 2 layers 4 layers RI (Rank Indication) 1 1 2

FIG. 19 illustrates PRB allocation. As shown in FIG. 19, a PRB may beused for PUCCH transmission in slot n_(s).

A multi-carrier system or a carrier aggregation system means a systemusing aggregation of a plurality of carriers having a bandwidth narrowerthan a target bandwidth for supporting wideband. When the plurality ofcarriers having a bandwidth narrower than the target bandwidth areaggregated, the bandwidth of the aggregated carriers may be limited tothe bandwidths used in existing systems for backward compatibility withthe existing systems. For example, an LTE system supports bandwidths of1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz and an LTE-A systemevolved from the LTE system can support bandwidths wider than 20 MHz byusing bandwidths supported by the LTE system. Alternatively, a newbandwidth may be defined to support carrier aggregation irrespective ofthe bandwidths used in existing systems. The term ‘multi-carrier’ can beused with carrier aggregation and bandwidth aggregation. Carrieraggregation collectively refers to both contiguous carrier aggregationand non-contiguous carrier aggregation.

FIG. 20 illustrates a concept of management of downlink componentcarriers in a BS and FIG. 21 illustrates a concept of management ofuplink component carriers in a UE. For convenience of description,higher layers are simply referred to as a MAC layer in the followingdescription.

FIG. 22 illustrates a concept of management of multiple carriers by oneMAC layer in a BS and FIG. 23 illustrates a concept of management ofmultiple carriers by MAC layer in a UE.

Referring to FIGS. 22 and 23, one MAC layer manages and operates one ormore frequency carriers for transmission and reception. In this case,resource management is flexible because frequency carriers managed byone MAC layer need not be contiguous. In FIGS. 22 and 23, one PHY layercorresponds to one component carrier. Here, one PHY layer does notnecessarily mean an independent radio frequency (RF) device. While oneindependent RF device means one PHY layer in general, one RF device isnot limited thereto and may include multiple PHY layers.

FIG. 24 illustrates a concept of management of multiple carriers bymultiple MAC layers in a BS and FIG. 25 illustrates a concept ofmanagement of multiple carriers by multiple MAC layers in a UE. FIG. 26illustrates a concept of management of multiple carriers by multiple MAClayers in a BS and FIG. 27 illustrates a concept of management ofmultiple carriers by one or more MAC layers in a UE.

Distinguished from the structures shown in FIGS. 22 and 23, multiplecarriers may be controlled by multiple MAC layers as shown in FIGS. 24to 27.

Multiple MAC layers may control one-to-one multiple carriers as shown inFIGS. 24 and 25. Referring to FIGS. 26 and 27, MAC layers may controlone-to-one some carriers and one MAC layer may control other carriers.

The above-described system includes one to N carriers which arecontiguous or non-contiguous. This can be applied in both uplink anddownlink. A TDD system is configured such that N carriers for downlinktransmission and uplink transmission are operated and an FDD system isconfigured such that multiple carriers are respectively used for uplinkand downlink. The FDD system may support asymmetrical carrieraggregation in which the numbers of aggregated carriers and/or carrierbandwidths are different between uplink and downlink.

When the number of aggregated component carriers in uplink equals thatof downlink, it is possible to configure all component carriers suchthat they are compatible with the existing systems. However, theconfigurations of component carriers that are not considered to becompatible with the existing systems are not excluded from the presentinvention.

While the following description is made on the assumption that, when aPDCCH is transmitted using downlink component carrier #0, a PDSCHcorresponding to the PDCCH is transmitted through downlink componentcarrier #0, it is apparent that the PDSCH can be transmitted through adifferent downlink component carrier using cross-carrier scheduling. Theterm ‘component carrier’ can be replaced with an equivalent term (e.g.cell).

FIG. 28 illustrates a scenario of transmitting UCI in a wirelesscommunication system that supports carrier aggregation. This scenario isbased on the assumption that UCI is ACK/NACK information. However, thisis exemplary and UCI can include control information such as channelstatus information (e.g. CQI, PMI, RI, etc.) and scheduling requestinformation (e.g. SR).

FIG. 28 illustrates asymmetrical carrier aggregation in which 5 DL CCsare linked to one UL CC. This asymmetrical carrier aggregation may beset from the viewpoint of UCI transmission. That is, DL CC-UL CC linkagefor the UCI and DL CC-UL CC linkage for data may be different from eachother. When it is assumed that one DL CC can transmit a maximum of twocodewords, at least two UL ACK/NACK bits are needed. In this case, atleast 10 ACK/NACK bits are necessary to transmit ACK/NACK informationfor data, received through 5 DL CCs, using one UL CC. If DTX status isalso supported for each DL CC, at least 12 bits (=5̂5=3125=11.6 bits) areneeded for ACK/NACK transmission. The conventional PUCCH formats 1a/1bcan transmit ACK/NACK information having a maximum of 2 bits, and thusit cannot transmit ACK/NACK information having an increased number ofbits. While it has been described that carrier aggregation increases thequantity of UCI, an increase in the number of antennas, presence of abackhaul subframe in a TDD system and a relay system, etc. may cause anincrease in the quantity of UCI. Similarly to ACK/NACK information, whencontrol information related to a plurality of DL CCs is transmittedthrough one UL CC, the quantity of the control information increases.For example, when CQI/PMI/RI related to a plurality of DL CCs istransmitted through, a UCI payload may increase. A DL CC and a UL CC mayalso be respectively called a DL cell and a UL cell and an anchor DL CCand an anchor UL CC may be respectively called a DL primary cell (PCell)and a UL PCell.

The DL primary CC may be defined as a DL CC linked with the UL primaryCC. Here, linkage includes both implicit linkage and explicit linkage.In LTE, one DL CC and one UL CC are uniquely paired. For example, a DLCC linked with the UL primary CC according to LTE paring can be calledthe DL primary CC. This can be regarded as implicit linkage. Explicitlinkage means that a network configures a linkage in advance and it maybe signaled through RRC. In explicit linkage, a DL CC paired with the ULprimary CC may be called the DL primary CC. Here, the UL primary(anchor) CC may be a UL CC that carries a PUCCH. Otherwise, the ULprimary CC may be a UL CC that carries UCI over a PUCCH or a PUSCH. TheDL primary CC can be configured through higher layer signaling. The DLprimary CC may be a DL CC through which a UE performs initial access. DLCCs other than the DL primary CC can be called DL secondary CCs.Similarly, UL CCs other than the UL primary CC can be called ULsecondary CCs.

DL-UL pairing may correspond to FDD only. DL-UL pairing may not beadditionally defined for TDD because TDD uses the same frequency. DL-ULlinkage may be determined from UL linkage through UL EARFCN informationof SIB2. For example, DL-UL linkage can be obtained through SIB2decoding in the event of initial access and acquired through RRCsignaling in other cases. Accordingly, only SIB2 linkage is present andother DL-UL pairing may not be explicitly defined. For example, in a5DL:1UL structure shown in FIG. 28, DL CC #0 and UL CC #0 is in a SIB2linkage relationship and other DL CCs may be in the SIB2 linkagerelationship with other UL CCs that are not set to the corresponding UE.

Although embodiments of the present invention are herein focused onasymmetric carrier aggregation, it is merely for illustrative purposeand the present invention can be applied to various carrier aggregationscenarios including symmetric carrier aggregation.

A scheme for efficiently transmitting an increased quantity of UCI willnow be described. Specifically, a new PUCCH format/signal processingprocedure/resource allocation method for transmitting an increasedquantity of UCI are proposed. In the following description, the PUCCHformat proposed by the present invention is referred to as a new PUCCHformat, LTE-A PUCCH format, or PUCCH format 3 in view of the fact thatup to PUCCH format 2 has been defined in LTE. The technical spirit ofthe PUCCH format proposed by the present invention can be easily appliedto an arbitrary physical channel (e.g. PUSCH) capable of transmittingUCI using the same or similar scheme. For example, an embodiment of thepresent invention can be applied to a periodic PUSCH structure thatperiodically transmits control information or an aperiodic PUSCHstructure that aperiodically transmits control information.

In the following description, the UCl/RS symbol structure of theexisting PUCCH format 1 (normal CP) of LTE is used as a subframe/slotlevel UCl/RS symbol structure applied to PUCCH format 3 according to anembodiment of the present invention. However, the subframe/slot levelUCl/RS symbol structure is exemplary and the present invention is notlimited to a specific UCl/RS symbol structure. In the PUCCH format 3according to the present invention, the number of UCl/RS symbols,positions of the UCl/RS symbols, etc. may be freely changed according tosystem designs. For example, the PUCCH format 3 according to the presentinvention can be defined using the RS symbol structures of the existingPUCCH format 2/2a/2b of LTE.

The PUCCH format 3 according to embodiments of the present invention canbe used to transmit arbitrary types/sizes of UCI. For example, the PUCCHformat 3 can transmit information such as ACK/NACK, CQI, PMI, RS, SR,etc. or a combination thereof. This information may have a payload of anarbitrary size. Description of the following embodiments and drawingsare focused on a case in which the PUCCH format 3 according to thepresent invention transmits ACK/NACK information.

Example 1

FIGS. 29a to 29f illustrate PUCCH format structures and signalprocessing procedures for the same according to an embodiment of thepresent invention.

FIG. 29a illustrates a case in which the PUCCH format according to thepresent invention is applied to PUCCH format 1 (normal CP). Referring toFIG. 29 a, a channel coding block channel-codes information bits a_0,a_1, . . . , a_M−1 (e.g. multiple ACK/NACK bits) to generate encodedbits (coded bits or coding bits) (or a codeword)) b_0, b_1, . . . ,b_N−1. Here, M denotes an information bit size and N denotes an encodedbit size. The information bits include multiple ACK/NACK bits for aplurality of data (or PDSCH) received through a plurality of DL CCs, forexample. The information bits a_0, a_1, . . . , a_M−1 are joint-codedregardless of the type/number/size of UCI that forms the informationbits. For example, when the information bits include multiple ACK/NACKbits for a plurality of DL CCs, channel coding is performed for allinformation bits instead of each DL CC and each ACK/NACK bit to generatea single codeword. Channel coding is not limited thereto and includessimplex repetition, simplex coding, RM coding, punctured RM coding,Tail-biting convolutional coding (TBCC), low-density parity-check (LDPC)or turbo-coding. The encoded bits can be rate-matched in considerationof a modulation order and resource quantity, which is not shown in thefigure. The rate matching function may be included in the channel codingblock or may be executed through a separate functional block. Forexample, the channel coding block can perform (32,0) RM coding onmultiple pieces of control information to generate a single codeword andcarry out circular buffer rate-matching on the codeword.

A modulator modulates the encoded bits b_0, b_1, . . . , b_N−1 togenerate modulation symbols c_0, c_1, . . . , c_L−1 where L denotes thesize of the modulation symbols. A modulation method is performed bymodifying the size and phase of a transmission signal. For example, themodulation method includes n-PSK (Phase Shift Keying) and n-QAM(Quadrature Amplitude Modulation) (n being an integer of 2 or greater).Specifically, the modulation method may include BPSK (Binary PSK), QPSK(Quadrature PSK), 8-PSK, QAM, 16-QAM, 64-QAM, etc.

A divider divides the modulation symbols c_0, c_1, . . . , c_L−1 intoslots. The order/pattern/scheme of dividing the modulation symbols intoslots are not particularly limited. For example, the divider cansequentially divide the modulation symbols into the slots (localizedscheme). In this case, modulation symbols c_0, c_1, . . . , c_L/2−1 canbe divided into slot 0 and modulation symbols c_L/2, c_L/2+1, . . . ,c_L−1 can be divided into slot 1, as shown in FIG. 29 a. Furthermore,the modulation symbols may be interleaved (or permuted) when dividedinto the slots. For example, even-numbered modulation symbols can bedivided into slot 0 and odd-numbered modulation symbols can be dividedinto slot 1. The order of the modulation operation and divisionoperation may be changed.

A DFT precoder performs DFT precoding (e.g. 12-point DFT) for themodulation symbols divided into each slot in order to generate a singlecarrier waveform. Referring to FIG. 29 a, the modulation symbols c_0,c_1, . . . , c_L/2−1 divided into slot 0 can be DFT-precoded into DFTsymbols d_0, d_1, . . . , d_L/2−1 and the modulation symbols c_L/2,c_L/2+1, . . . , c_L−1 divided into slot 1 can be DFT-precoded into DFTsymbols d_L/2, d_L/2+1, . . . , d_L−1. DFT precoding can be replaced byother corresponding linear operations (e.g. Walsh precoding).

A spreading block spreads the DFT precoded signal at an SC-FDMA symbollevel (time domain). Time domain spreading at an SC-FDMA symbol level isperformed using a spreading code (sequence). The spreading code includesa quasi-orthogonal code and an orthogonal code. The quasi-orthogonalcode includes a pseudo noise (PN) code. However, the quasi-orthogonalcode is not limited thereto. The orthogonal code includes a Walsh codeand a DFT code. However, the orthogonal code is not limited thereto. Inthe following description, the orthogonal code is used as the spreadingcode for ease of description. However, the orthogonal code is exemplaryand can be replaced by the quasi-orthogonal code. The maximum value ofspreading code size (or spreading factor SF) is limited by the number ofSC-FDMA symbols used for control information transmission. For example,when 4 SC-FDMA symbols are used for control information transmission inone slot, a (quasi) orthogonal code w0,w1,w2,w3 having a length of 4 canbe used for each slot. The SF means a spreading degree of controlinformation and may be related to a UE multiplexing order or an antennamultiplexing order. The SF can be changed to 1, 2, 3, 4, . . . accordingto system requirements, and pre-defined between a BS and a UE orsignaled to the UE through DCI or RRC signaling. For example, when oneof SC-FDMA symbols for control information is punctured in order totransmit an SRS, a spreading code with a reduced SF (e.g. SF=3 insteadof SF=4) can be applied to control information of the correspondingslot.

The signal generated through the above-mentioned procedure is mapped tosubcarriers in a PRB and then subjected to IFFT to be transformed into atime domain signal. A cyclic prefix is added to the time domain signalto generate SC-FDMA symbols which are then transmitted through an RFunit.

The above-mentioned procedure will now be described in more detail onthe assumption that ACK/NACK bits for 5 DL CCs are transmitted. Wheneach DL CC can transmit 2 PDSCHs, ACK/NACK bits for the DL CC may be 12bits if a DTX status is included. A coding block size (after ratematching) may be 48 bits on the assumption that QPSK and SF=4 timespreading are used. Encoded bits are modulated into 24 QPSK symbols and12 QPSK symbols are divided into each slot. In each slot, 12 QPSKsymbols are converted to 12 DFT symbols through 12-point DFT. In eachslot, 12 DFT symbols are spread and mapped to 4 SC-FDMA symbols using aspreading code with SF=4 in the time domain. Since 12 bits aretransmitted through [2 bits×12 subcarriers×8 SC-FDMA symbols], thecoding rate is 0.0625(=12/192). In the case of SF=4, a maximum of 4 UEscan be multiplexed per PRB.

The signal mapped to the PRB in the procedure shown in FIG. 29a may beobtained through various equivalent signal processing procedures. Signalprocessing procedures equivalent to the signal processing procedure ofFIG. 29a will now be described with reference to FIGS. 29b to 29 g.

FIG. 29b shows a case in which the order of operations of the DFTprecoder and the spreading block of FIG. 29a is changed. The function ofthe spreading block corresponds to operation of multiplying a DFT symbolsequence output from the DFT precoder by a specific constant at theSC-FMDA symbol level, and thus the same signal value is mapped toSC-FDMA symbols even though the order of operations of the DFT precoderand the spreading block is changed. Accordingly, the signal processingprocedure for the PUCCH format 3 can be performed in the order ofchannel coding, modulation, division, spreading and DFT precoding. Inthis case, the division and spreading may be performed by one functionalblock. For example, modulation symbols can be alternately divided intoslots and, simultaneously, spread at the SC-FDMA symbol level.Alternatively, the modulation symbols can be copied such that theycorrespond to the size of a spreading code when divided into the slots,and the copied modulation symbols can be multiplied one-to-one byrespective elements of the spreading code. Accordingly, a modulationsymbol sequence generated for each slot is spread to a plurality ofSC-FDMA symbols. Then, a complex symbol sequence corresponding to theSC-FDMA symbols is DFT-precoded for each SC-FDMA symbol.

FIG. 29c shows a case in which the order of operations of the modulatorand the divider of FIG. 29a is changed. In this case, in the signalprocessing procedure for PUCCH format 3, joint channel coding anddivision are performed at the subframe level, and modulation, DFTprecoding and spreading are sequentially performed at the slot level.

FIG. 29d shows a case in which the order of operations of the DFTprecoder and the spreading block of FIG. 29c is changed. As describedabove, since the function of the spreading block corresponds tooperation of multiplying a DFT symbol sequence output from the DFTprecoder by a specific constant at the SC-FMDA symbol level, the samesignal value is mapped to SC-FDMA symbols even though the order ofoperations of the DFT precoder and the spreading block is changed.Accordingly, in the signal processing procedure for PUCCH format 3,joint channel coding and division are performed at the subframe level,and modulation is carried out at the slot level. The modulation symbolsequence generated for each slot is spread to a plurality of SC-FDMAsymbols and DFT-precoded for each SC-FDMA symbol. In this case, themodulation and spreading operations can be performed by one functionalblock. For example, the generated modulation symbols can be directlyspread at the SC-FDMA symbol level during modulation of the encodedbits. Alternatively, during modulation of the encoded bits, thegenerated modulation symbols can be copied such that they correspond tothe size of the spreading code and multiplied one-to-one by respectiveelements of the spreading code.

FIG. 29e shows a case in which PUCCH format 3 according to the presentembodiment is applied to PUCCH format 2 (normal CP) and FIG. 29f shows acase in which PUCCH format 3 according to the present embodiment isapplied to PUCCH format 2 (extended CP). While a basic signal processingprocedure is the same as the procedures described with reference toFIGS. 29a to 29 d, the numbers/positions of UCI SC-FDMA symbols and RSSC-FDMA symbols are different from those of FIG. 29a since PUCCH format2 of LTE is reused.

Table 14 shows RS SC-FDMA symbol position in the PUCCH format 3. It isassumed that the number of SC-FDMA symbols in a slot is 7 (indexes: 0 to6) in case of normal CP and 6 (indexes: 0 to 5) in case of extended CP.

TABLE 14 RS SC-FDMA symbol position Normal CP Extended CP Note PUCCH 2,3, 4 2, 3 Reuse PUCCH format 1 format 3 1, 5 3 Reuse PUCCH format 2

Tables 15 and 16 show exemplary spreading codes according to SF value.Table 15 shows DFT codes with SF=5 and SF=3 and Table 16 shows Walshcodes with SF=4 and SF=2. A DFT code is an orthogonal code representedby w _(m)=[w₀,w₁ . . . w_(k−1)], where w_(k)=exp(j2πkm/SF) where kdenotes a DFT code size or SF value and m is 0,1, . . . , SF−1. Tables15 and 16 show a case in which m is used as an index for orthogonalcodes.

TABLE 15 Orthogonal code w _(m) = [w₀ w₁ . . . w_(k−1)] Index m SF = 5SF = 3 0 [1 1 1 1 1] [1 1 1] 1 [1 e^(j2π/5) e^(j4π/5) e^(j6π/5)e^(j8π/5)] [1 e^(j2π/3) e^(j4π/3)] 2 [1 e^(j4π/5) e^(j8π/5) e^(j2π/5)e^(j6π/5)] [1 e^(j4π/3) e^(j2π/3)] 3 [1 e^(j6π/5) e^(j2π/5) e^(j8π/5)e^(j4π/5)] 4 [1 e^(j8π/5) e^(j6π/5) e^(j4π/5) e^(j2π/5)]

TABLE 16 Orthogonal code Index m SF = 4 SF = 2 0 [+1 +1 +1 +1] [+1 +1] 1[+1 −1 +1 −1] [+1 −1] 2 [+1 +1 −1 −1] 3 [+1 −1 −1 +1]

Code index m may be designated in advance or signaled from the BS. Forexample, the code index m can be implicitly linked with a CCE index(e.g. the lowest CCE index) constituting a PDCCH. The code index m maybe explicitly designated through a PDCCH or RRC signaling. Furthermore,the code index m may be derived from a value designated through thePDCCH or RRC signaling. The code index m may be independently given foreach subframe, each slot, and multiple SC-FDMA symbols. Preferably, thecode index m can be changed for each subframe, each slot and multipleSC-FDMA symbols. That is, the code index m can be hopped at apredetermined interval.

Cell-specific scrambling using a scrambling code (e.g. a PN code such asa Gold code) corresponding to a physical cell ID (PCI) or UE-specificscrambling using a scrambling code corresponding to a UE ID (e.g. RNTI)can be additionally applied for inter-cell interference randomization,which is not shown in the figure. Scrambling may be performed for theentire information, performed in SC-FDMA symbols, carried out betweenSC-FDMA symbols, or carried out for both the entire information andSC-FDMA symbols. Scrambling the entire information can be achieved byperforming scrambling on the information bits, encoded bits andmodulation symbols prior to division. Intra-SC-FMDA symbol scramblingmay be implemented by performing scrambling on the modulation symbols orDFT symbols after division. Inter-SC-FDMA symbol scrambling may beachieved by carrying out scrambling on the SC-FDMA symbols in the timedomain after spreading.

UE multiplexing can be achieved by applying CDM before being subjectedto the DFT precoder. For example, the signal before being subjected tothe DFT precoder is a time domain signal, and thus CDM can beimplemented through circular shift (or cyclic shift) or Walsh (or DFT)spreading. CDM can be performed at the information bit level, encodedbit level and modulation symbol level. Specifically, a case ofmultiplexing 2 UEs to one SC-FDMA symbol using a Walsh code with SF=2 isexemplified. When QPSK is performed on 12 encoded bits, a complex signalof a₀a₁a₂a₃a₄a₅ is generated. An example of spreading controlinformation of each UE using Walsh code [+1 +1] [+1 −1] is as follows.

-   -   UE #0: [+1 +1] is applied. a₀a₁a₂a₃a₄a₅a₀a₁a₂a₃a₄a₅ are        transmitted.    -   UE #1: [+1 −1] is applied. a₀a₁a₂a₃a₄a₅−a₀−a₁−a₂−a₃−a₄−a₅ are        transmitted.

In this case, interleaving may be additionally performed. Theinterleaving may be applied before or after spreading. An example ofapplying both the spreading and interleaving is as follows.

-   -   UE #0: [+1 +1] is applied. a₀a₀a₁a₁a₂a₂a₃a₃a₄a₄a₅a₅ are        transmitted.    -   UE #1: [+1 −1] is applied.        a₀,−a₀,a₁,−a₁,a₂,−a₂,a₃,−a₃,a₄,−a₄,a₅,−a₅ are transmitted.

A signal generated from spreading and/or interleaving in a stage priorto the DFT precoder is subjected to DFT precoding (and additionallysubjected to time spreading at the SC-FDMA symbol level as necessary)and mapped to subcarriers of the corresponding SC-FDMA symbols.

FIG. 30 illustrates another exemplary PUCCH format according to thepresent embodiment of the invention. While the PUCCH format shown inFIG. 30 has the same basic structure as that of the PUCCH format shownin FIG. 29, the PUCCH format of FIG. 30 is different from the PUCCHformat of FIG. 29 in that the same encoded bits are repeated on aslot-by-slot basis. Accordingly, a signal processing block shown in FIG.30 does not include a divider.

A description will be given of methods of allocating a PUCCH resource toa UE on the assumption that multiple ACK/NACK bits are transmitted fordata received through a plurality of DL CCs. For convenience ofdescription, the PUCCH resource includes a resource for controlinformation transmission and/or a resource for RS transmission and it isassumed that a (quasi) orthogonal resource for control informationtransmission is referred to as resource A and a (quasi) orthogonalresource for RS transmission is referred to as resource B. Resource Aincludes at least one of a PRB index and a spreading code (e.g. Walshcode) index. One representative logical index may be given for resourceA and the PRB index and spreading code index may be derived from therepresentative logical index. Resource B includes at least one of a PRBindex, a circular shift index and an orthogonal cover index. Onerepresentative logical index may be given for resource B, and the PRBindex, circular shift index and orthogonal cover index may be inferredfrom the representative logical index. The logical indexes of resource Aand resource B may be linked with each other. Furthermore, indexes ofresources constituting resource A and resource B may be linked with eachother. Alternatively, a separate (representative) PUCCH resource indexmay be defined and linked with resource A and/or resource B. That is,resource A and/or resource B may be inferred from the separate PUCCHresource index.

A first resource allocation method signals both resource A and resourceB. For example, both resource A and resource B can be signaled throughphysical control channel (e.g. PUCCH) or RRC signaling. In this case,the resource A index for control information transmission and theresource B index for RS transmission may be respectively signaled oronly one thereof may be signaled. For example, if RS format and indexingconform to LTE, only resource B index for RS transmission can besignaled. Because it is preferable to transmit control information inthe same PRB as that of the RS, the PRB index for the controlinformation may be derived from the resource B index for the RS, and thecontrol information may be transmitted through a PRB corresponding tothe PRB index. The orthogonal code index used for the controlinformation may be derived from the orthogonal cover index or circularshift index used for the RS. Alternatively, it is possible to signal anadditional PUCCH resource index and infer resource A and/or resource Bfrom the additional PUCCH resource index. That is, when the additionalPUCCH resource index is given, the PRB and/or the orthogonal cover indexfor the control information and the PRB, orthogonal cover index and/orcircular shift index for the RS can be inferred from the additionalPUCCH resource index.

To reduce signaling overhead and efficiently use resources, a pluralityof candidate PUCCH resources (indexes) can be signaled to a UE or a UEgroup through higher layer signaling (e.g. RRC signaling) and a specificPUCCH resource (index) can be indicated through a physical controlchannel (e.g. PDCCH). As described above, a PUCCH resource (index) canbe given as [resource A index and resource B index], [resource A indexor resource B index] or [separate PUCCH resource index]. Specifically,the PUCCH resource index can be signaled through a PDCCH of a DLsecondary CC. When carrier aggregation is applied, transmit powercontrol (TPC) of a DL secondary CC need not be used because a PUCCH istransmitted through the UL primary CC only. Accordingly, the PUCCHresource (index) can be signaled through a TPC field of a PDCCHtransmitted through a DL secondary CC.

A second resource allocation method reuses the implicit method of LTE incase of dynamic ACK/NACK resource allocation. For example, a resourceindex that corresponds to the lowest CCE index of a PDCCH correspondingto a DL grant of a specific DL CC (e.g. primary DL CC) and conforms toLTE rule (n_(r)=n_(cce)+N_PUCCH⁽¹⁾ can be inferred. Here, n_(r) denotesthe resource A (and/or resource B) index, n_(cce) denotes the lowest CCEindex constituting the PDCCH, and N_PUCCH⁽¹⁾ denotes a value configuredby a higher layer. For example, the RS can use a resource correspondingto the inferred resource index. In the case of control information, thePRB index can be derived from the inferred resource index and ACK/NACKinformation for a plurality of DL CCs can be transmitted using acorresponding resource (e.g. spreading code) in the PRB corresponding tothe PRB index. When the resource index corresponding to the RS isinferred from the resource index corresponding to the controlinformation, the circular shift index used for the RS cannot be derivedfrom the resource index corresponding to the control information becausethe resource corresponding to the circular shift index from among RSresources (e.g. a combination of the circular shift, orthogonal coverand PRB index) is not used for the control information.

A scheme of transmitting a PUCCH using a multi-antenna transmissionmethod will now be described. While 2Tx transmit diversity scheme isdescribed in the following embodiment, the embodiment can beequally/similarly applied to an n-Tx transmit diversity scheme. It isassumed that a (quasi) orthogonal resource for control informationtransmission is referred to as resource A and a (quasi) orthogonalresource for RS transmission is referred to as resource B. Logicalindexes of resource A and resource B may be liked with each other. Forexample, if the logical index of resource B is given, the logical indexof resource A can be automatically provided. The logical indexes ofresource A and resource B may be configured through different physicalconfiguration methods. The following two cases are present.

1) Control information can be transmitted through the same PRB at allantennas (ports).

A. The control information can be transmitted through two differentresources A (e.g. Walsh or DFT codes with different indexes) selectedfor each antenna (port).

B. An RS can be transmitted through two different resources B (e.g. acombination of a circular shift and a DFT cover) selected for eachantenna (port).

2) The control information can be transmitted through different PRBs forantennas. For example, the control information can be transmittedthrough PRB #4 at antenna (port) 0 and transmitted through PRB #6 atantenna (port) 1.

A. Resources for the control information transmitted through differentantennas (ports) are not particularly limited (i.e. the resources can beequal to and different from each other).

B. Resources for RSs transmitted through different antennas (ports) arenot particularly limited (i.e. the resources can be equal to anddifferent from each other).

In a multi-antenna transmit (e.g. 2Tx transmit) mode, two resources A(e.g. orthogonal codes) for control information transmission and tworesources B (e.g. a combination of a circular shift and a DFT cover) forRS transmission can be defined in advance or provided through physicalcontrol channel (e.g. PDCCH)/RRC signaling. In this case, signaling forthe control information and RS can be individually performed. Whenresource information for one antenna (port) is signaled, resourceinformation for the other antenna (port) can be inferred from thepreviously signaled resource information. For example, the spreadingcode index m for the control information can be designated in advance orsignaled from the BS. Otherwise, the spreading code index m can beimplicitly linked with a CCE index that configures a PDCCH. Or, thespreading code index m can be explicitly designated through PDCCH or RRCsignaling. The spreading code index m can be linked with the orthogonalcode index or circular shift index for the RS. The spreading code indexm can be changed on a subframe, slot or multi-SC-FDMA symbol basis. Thatis, the spreading code index m can be hopped in the unit of a specificinterval (e.g. slot).

Example 2

FIGS. 31 and 32 illustrate PUCCH format structures and signal processingprocedures for the same according to another embodiment of the presentinvention. In the present embodiment, control information is FDM-mappedto the frequency domain according to interleaving and local schemes. FDMmapping can be used for UE multiplexing or antenna (port) multiplexing.The present embodiment can be applied to CDM mapping usingtime/frequency domain cyclic shift.

Referring to FIG. 31, a channel coding block channel-codes informationbits a_0, a_1, . . . , a_M−1 (e.g. multiple ACK/NACK bits) to generateencoded bits (coded bits or coding bits) (or a codeword) b_0, b_1, . . ., b_N−1. Here, M denotes an information bit size and N denotes anencoded bit size. The information bits include multiple ACK/NACK bits,for example. The information bits a_0, a_1, . . . , a_M−1 arejoint-coded regardless of the type/number/size of UCI that forms theinformation bits. For example, when the information bits includemultiple ACK/NACK bits for a plurality of DL CCs, channel coding is notperformed per each DL CC or individual ACK/NACK bit but performed forall information bits, thereby generating a single codeword. Channelcoding is not limited thereto and includes simple repetition, simplexcoding, RM coding, punctured RM coding, Tail-biting convolutional coding(TBCC), low-density parity-check (LDPC) or turbo-coding. The encodedbits can be rate-matched in consideration of a modulation order andresource quantity, which is not shown in the figure. The rate matchingfunction may be included in the channel coding block or may be executedthrough a separate functional block.

A modulator modulates the encoded bits b_0, b_1, . . . , b_N−1 togenerate modulation symbols c_0, c_1, . . . , c_L−1 where L denotes thesize of the modulation symbols. A modulation method is performed bymodifying the size and phase of a transmission signal. For example, themodulation method includes n-PSK (Phase Shift Keying) and n-QAM(Quadrature Amplitude Modulation) (n being an integer of 2 or greater).Specifically, the modulation method may include BPSK (Binary PSK), QPSK(Quadrature PSK), 8-PSK, QAM, 16-QAM, 64-QAM, etc.

A divider divides the modulation symbols c_0, c_1, . . . , c_L−1 intoslots. The order/pattern/scheme of dividing the modulation symbols intoslots are not particularly limited. For example, the divider cansequentially divide the modulation symbols into the slots (localizedtype). In this case, modulation symbols c_0, c_1, . . . , c_L/2−1 can bedivided into slot 0 and modulation symbols c_L/2, c_L/2+1, . . . , c_L−1can be divided into slot 1, as shown in FIG. 29 a. Furthermore, themodulation symbols may be interleaved (or permuted) when divided intothe slots. For example, even-numbered modulation symbols can be dividedinto slot 0 and odd-numbered modulation symbols can be divided into slot1. The order of the modulation operation and division operation may bechanged.

A DFT precoder performs DFT precoding (e.g. 6-point DFT) for themodulation symbols divided into each slot in order to generate a singlecarrier waveform. Referring to FIG. 29 a, the modulation symbols c_0,c_1, . . . , c_L/2−1 divided into slot 0 can be DFT-precoded into DFTsymbols d_0, d_1, . . . , d_L/2−1 and the modulation symbols c_L/2,c_L/2+1, . . . , c_L−1 divided into slot 1 can be DFT-precoded into DFTsymbols d_L/2, d_L/2+1, . . . , d_L−1. DFT precoding can be replaced byanother corresponding linear operation (e.g. Walsh precoding).

A spreading block spreads the DFT precoded signal at an SC-FDMA symbollevel (time domain). Time domain spreading at an SC-FDMA symbol level isperformed using a spreading code (sequence). The spreading code includesa quasi-orthogonal code and an orthogonal code. The orthogonal codeincludes a Walsh code and a DFT code. However, the orthogonal code isnot limited thereto. The maximum spreading code size (or spreadingfactor SF) is limited by the number of SC-FDMA symbols used for controlinformation transmission. For example, when 4 SC-FDMA symbols are usedfor control information transmission in one slot, a (quasi) orthogonalcode w0,w1,w2,w3 having a length of 4 can be used for each slot. The SFmeans a spreading degree of control information and may be related to aUE multiplexing order or an antenna multiplexing order. The SF can bechanged to 1, 2, 3, 4, . . . according to system requirements, andpre-defined between a BS and a UE or signaled to the UE through DCI orRRC signaling. For example, when an SC-FDMA symbol for transmittingcontrol information according to an SRS, a spreading code with SF=3 canbe applied to control information of the corresponding slot. Examples ofthe spreading code may refer to Tables 15 and 16.

The signal generated through the above-mentioned procedure is mapped tosubcarriers in a PRB. Distinguished from the first embodiment, thespread signal is non-contiguously mapped to the subcarriers in SC-FDMAsymbols. FIG. 31 shows a case in which the spread signal is mapped inthe SC-FDMA symbols in an interleaving manner and FIG. 32 shows a casein which the spread signal is mapped in the SC-FDMA symbols in alocalized manner. The frequency domain signal mapped to the subcarriersis transformed to a time domain signal through IFFT. A CP is added tothe time domain signal to generate SC-FDMA symbols which are thentransmitted through an RF unit.

The above-mentioned procedure will now be described in more detail onthe assumption that ACK/NACK bits for 5 DL CCs are transmitted. Wheneach DL CC can transmit 2 PDSCHs, ACK/NACK bits for the DL CC may be 12bits when a DTX status is included. A coding block size (after ratematching) may be 24 bits on the assumption that QPSK, SF=4 timespreading and non-contiguous mapping are used. Encoded bits aremodulated into 12 QPSK symbols and 6 QPSK symbols are divided into eachslot. In each slot, 6 QPSK symbols are converted to 6 DFT symbolsthrough 6-point DFT. In each slot, 6 DFT symbols are spread and mappedto 4 SC-FDMA symbols using a spreading code with SF=4 in the timedomain. Since 12 bits are transmitted through [2 bits×6 subcarriers×8SC-FDMA symbols], the coding rate is 0.125(=12/96). In the case of SF=4,a maximum of 8 UEs can be multiplexed per PRB.

If a subcarrier spacing is changed from 2 blocks to 3 blocks when theDFT symbols are mapped to the frequency domain, a maximum of 12 UEs canbe multiplexed. When the subcarrier interval is configured to 4/6blocks, a maximum of 16/24 UEs can be multiplexed. Here, the RS canemploy the DFT code with SF=3 and circular shift used in LTE. In thecase of a Walsh code with SF=4 in LTE, [1 1 −1 −1] is not used becausethe multiplexing order is limited by SF=3 of the RS. However, thepresent invention can define [1 1 −1 −1] such that it can be reused.

Cell-specific scrambling using a scrambling code (e.g. a PN code such asa Gold code) corresponding to a physical cell ID (PCI) or UE-specificscrambling using a scrambling code corresponding to a UE ID (e.g. RNTI)can be additionally applied for inter-cell interference randomization,which is not shown in the figure. Scrambling may be performed for theentire information, performed in SC-FDMA symbols, carried out betweenSC-FDMA symbols, or carried out for both the entire information andSC-FDMA symbols. Scrambling the entire information can be achieved byperforming scrambling at the information bit level, encoded bit level ormodulation symbol level prior to division. Intra-SC-FMDA symbolscrambling may be implemented by performing scrambling on the modulationsymbols or DFT symbols after division. Inter-SC-FDMA symbol scramblingmay be achieved by carrying out scrambling on the SC-FDMA symbols in thetime domain after spreading.

UE multiplexing can be achieved by applying CDM to a signal before beingsubjected to the DFT precoder. For example, the signal before beingsubjected to the DFT precoder is a time domain signal, and thus CDM canbe implemented through circular shift (or cyclic shift) or Walsh (orDFT) spreading. CDM multiplexing can be performed for one at theinformation bit level, encoded bit level and modulation symbol level.Specifically, a case of multiplexing 2 UEs to one SC-FDMA symbol using aWalsh code with SF=2 is exemplified. When QPSK is performed on 6-bitencoded bits, a complex signal of a₀,a₁,a₂ is generated. Controlinformation of each UE is spread using Walsh code [+1 +1] [+1 −1] asfollows.

-   -   UE #0: [+1 +1] is applied. a₀,a₁,a₂,a₀,a₁,a₂ are transmitted.    -   UE #1: [+1 −1] is applied. a₀,a₁,a₂,−a₀,−a₁,−a₂ are transmitted.

In this case, interleaving may be additionally performed. Theinterleaving may be applied before or after spreading. Both thespreading and interleaving are applied as follows.

-   -   UE #0: [+1 +1] is applied. a₀,a₀,a₁,a₁,a₂,a₂ are transmitted.    -   UE #1: [+1 −1] is applied. a₀,−a₀,a₁,−a₁,a₂,−a₂ are transmitted.

FIGS. 33 and 34 illustrate another exemplary PUCCH format according tothe present embodiment of the invention. While the PUCCH format shown inFIGS. 33 and 34 has the same basic structure as that of the PUCCHformats shown in FIGS. and 32, the PUCCH format of FIGS. 33 and 34 isdistinguished from the PUCCH format of FIGS. 31 and 32 in that the sameencoded bits are repeated on a slot-by-slot basis. Accordingly, a signalprocessing block shown in FIGS. 33 and 34 does not include a divider.

A description will be given of methods of allocating a PUCCH resource toa UE on the assumption that multiple ACK/NACK bits are transmitted fordata received through a plurality of DL CCs. For convenience ofdescription, it is assumed that a (quasi) orthogonal resource forcontrol information transmission is referred to as resource A and a(quasi) orthogonal resource for RS transmission is referred to asresource B. Resource A includes at least one of a PRB index, a spreadingcode (e.g. Walsh code) index and a subcarrier shift (or offset or index)according to frequency factor. One representative logical index may begiven for resource A and the PRB index, spreading code index and asubcarrier shift (or offset or index) according to frequency factor maybe derived from the representative logical index. Resource B includes atleast one of a PRB index, a circular shift index and an orthogonal coverindex. One representative logical index may be given for resource B, andthe PRB index, circular shift index and orthogonal cover index may beinferred from the representative logical index. The logical indexes ofresource A and resource B may be linked with each other. Furthermore,indexes of resources constituting resource A and resource B may belinked with each other.

A first resource allocation method signals both resource A and resourceB. For example, both resource A and resource B can be signaled throughphysical control channel (e.g. PUCCH) or RRC signaling. In this case,the resource A index for control information transmission and theresource B index for RS transmission may be respectively signaled oronly one thereof may be signaled. For example, if RS format and indexingconform to LTE, only resource B index for RS transmission can besignaled. Because it is preferable to transmit control information inthe same PRB as that of the RS, the PRB index for the controlinformation may be derived from the resource B index for the RS and thecontrol information may be transmitted through a PRB corresponding tothe PRB index. The orthogonal code index used for the controlinformation may be derived from the orthogonal cover index or circularshift index used for the RS. The subcarrier shift (or offset or index)according to frequency factor for resource A may be inferred from thecircular shift index used for the RS. Alternatively, the subcarriershift (or offset or index) according to frequency factor for resource Amay be RRC signaled. Here, the frequency factor (or linear operationcorresponding thereto, e.g. the reciprocal of the frequency factor) canbe RRC signaled or implicitly determined on the basis of the number ofDL CCs. That is, the frequency factor can be configured by the system orpreviously designated.

FDM mapping can also be applied to the RS. The RS can be directlygenerated in the frequency domain without a DFT precoder (i.e. the DFTprecoder can be omitted) because a previously designated low-CM sequenceis used whereas a low PAPR/CM signal is generated using DFT precoding inthe case of control information. However, it may be technicallypreferable to apply CDM mapping using circular shift to the RS ratherthan FDM mapping for the following reason.

-   -   Design of sequences with various lengths is required when FDM        mapping is used for the RS. That is, a new sequence with a        length of 6 is needed when a frequency factor (FF) (or        subcarrier interval) is 2 although a minimum sequence length for        the RS is 12 in LTE.    -   When FDM mapping is used for the RS, channel estimation        performance may be deteriorated in a high frequency selective        channel because a channel of a specific frequency position is        estimated and interpolation is performed on other positions.        However, the channel estimation performance is not deteriorated        because the RS covers all frequency regions in the case of CDM        mapping.

A second resource allocation method reuses the implicit method of LTE incase of dynamic ACK/NACK resource allocation. For example, a resourceindex that corresponds to the lowest CCE index of a PDCCH correspondingto a DL grant of a specific DL CC (e.g. primary DL CC) and conforms toLTE rule (n_(r)=n_(cce)+N_PUCCH⁽¹⁾) can be inferred. Here, n_(r) denotesthe resource A (and/or resource B) index, n_(cce) denotes the lowest CCEindex constituting the PDCCH, and N_PUCCH⁽¹⁾ denotes a value configuredby higher layers. For example, the RS can use a resource correspondingto the inferred resource index. In the case of control information, thePRB index can be derived from the inferred resource index and ACK/NACKinformation for a plurality of DL CCs can be transmitted using acorresponding resource (e.g. spreading code and/or subcarrier shift (oroffset or index) according to frequency factor) in the PRB correspondingto the PRB index. When the resource index corresponding to the RS isinferred from the resource index corresponding to the controlinformation, the circular shift index used for the RS cannot be derivedfrom the resource index corresponding to the control information becausethe resource corresponding to the circular shift index from among RSresources (e.g. a combination of the circular shift, orthogonal coverand PRB index) is not used for the control information.

FIGS. 35 to 41 illustrate a method of defining a resource indexaccording to an embodiment of the present invention. FIGS. 35 and 41show a case in which a resource index (i.e. resource A index) forcontrol information is defined as a combination of a subcarrier mappingpattern/position (e.g. subcarrier index of offset) and a spreading code(e.g. orthogonal code). When a PRB for RS transmission is confirmed, aPRB for control information transmission can be configured as the PRBfor RS transmission. Otherwise, the PRB for control informationtransmission can be signaled through physical control channel (e.g.PDCCH)/RRC signaling. In the present embodiment, a subcarrier shift (oroffset or index) according to frequency factor for the controlinformation can be inferred from the circular shift index of the RS.Otherwise, the subcarrier shift (or offset or index) according tofrequency factor can be RRC signaled. Here, the frequency factor can beRRC signaled or implicitly determined on the basis of the number of DLCCs. That is, the frequency factor can be configured by the system orpreviously designated. In this case, a representative index forindicating a combination (e.g. [PRB, spreading code] or [PRB, spreadingcode, frequency factor]) of detailed resources may not be separatelydefined in a channel resource for the control information.

Referring to FIGS. 35 to 41, numerals in boxes mean resource indexes(i.e. resource A indexes for control information transmission). In thepresent embodiment, resource indexes for the control information arelinked with [orthogonal code indexes, subcarrier shifts (or offsets orindexes)]. Accordingly, the control information is spread at the SC-FDMAsymbol level using an orthogonal code corresponding to resource indexesand mapped to subcarriers corresponding to the resource indexes. Whilethe resource indexes are counted in ascending order of frequencyresource (subcarrier index) in FIGS. 35 to 41, the resource indexes maybe counted on the basis of the orthogonal code index axis. FIGS. 35 b,36 b, 37 b, 38 b, 39 b and 40 b show that resource indexing for thecontrol information is limited by an RS multiplexing order. For example,if the RS multiplexing order is 3 and a Walsh code with SF=4 is used forcontrol information transmission, [+1 +1 −1 −1] (resource index 3) maynot be used, as in LTE.

The resource indexes may be relative values (e.g. offset). For example,PUCCH format 2/2a/2b may be transmitted through the outermost portion ofa band, 1 PRB in which PUCCH formats 1/1a/1b and 2/2a/2b coexist may belocated inside the outermost portion of the band, and PUCCH format1/1a/1b may be transmitted through a portion inside the portion wherePUCCH formats 1/1a/1b and 2/2a/2b coexist in LTE. When a PRB for PUCCHformat 1/1a/1b and a PRB for PUCCH format 2/2a/2b are present together(only one PRB is allowed in LTE), if the number of ACK/NACK resources isM in the corresponding PRBs, n represents M+n. Here, each frequencyresource (e.g. frequency factor) or orthogonal code index can becell-specifically/UE-specifically hopped at the SC-FDMA symbollevel/slot level.

FIG. 41 illustrates a case in which orthogonal resource indexes arestaggered for each orthogonal code index or circularly shifted along thefrequency axis. In this case, the resource indexes in FIG. 37a arestaggered subcarrier by subcarrier for each orthogonal code index.Circular shifts or orthogonal code indexes can becell-specifically/UE-specifically hopped at the SC-FDMA symbollevel/slot level.

FIG. 42 illustrates a resource indexing method for an RS. Resourceindexing for an RS may conform to the method defined in LTE.

Referring to FIG. 42, numerals in boxes denote resource indexes (i.e.indexes of resource B for RS transmission). In this example, theresource indexes for the RS are linked with [circular shift values,orthogonal code indexes]. Accordingly, an RS sequence iscircular-shifted by a value corresponding to a resource index along thefrequency axis and covered in the time domain with an orthogonal codecorresponding to the resource index. In FIG. 42, Δ_(shift) ^(PUCCH)denotes a circular shift interval and a used circular shift value may bec·Δ_(shift) ^(PUCCH) (c being a positive integer). A phase shift valueaccording to a circular shift can be given asα(n_(s),l)=2π·n_(cs)(n_(s),l)/N_(sc) ^(RB) where n_(s) is a slot index,l is an SC-FDMA symbol index, n_(s)(n_(s),l) is a circular shift value,and N^(RB) _(sc) denotes the number of subcarriers that form a resourceblock.

In this example, the resource indexes for the RS are counted first alongthe circular shift axis. However, the resource indexes may be countedfirst along the orthogonal code axis.

Δ_(shift) ^(PUCCH) of the RS and the frequency factor of controlinformation (or a corresponding linear operation, e.g. the reciprocal ofthe frequency factor) can be signaled through physical control channel(e.g. PDCCH) or RRC signaling.

Resource indexing for the control information may correspond to resourceindexing for the RS. In this case, only one of the control informationresource index and RS resource index may be signaled to a UE throughphysical control channel (e.g. PDCCH)/RRC signaling and the other may beinferred from the resource index signaled to the UE. For example, thefrequency factor can be inferred from information (e.g. the circularshift spacing) about circular shift used in the RS. If conventionalΔ_(shift) ^(PUCCH) signaling is reused, both Δ_(shift) ^(PUCCH) for theRS and the frequency factor (interval) for the control information canbe designated through one-time Δ_(shift) ^(PUCCH) signaling.Specifically, they are associated with resource indexing shown in FIG.42 and resource indexing shown in FIGS. 35 b, 36 b, 37 b, 38 b, 39 b and40 b, respectively.

Table 17 shows an example of mapping Δ_(shift) ^(PUCCH) and thefrequency factor.

TABLE 17 Δ_(shift) ^(PUCCH) Frequency Factor (FF) 1 1 2 2 3 3 4 4 6 6 1212

Table 18 shows an example of mapping Δ_(shift) ^(PUCCH) and thefrequency factor in consideration of the number of available resources(i.e. multiplexing order). For example, when the multiplexing orderaccording to circular shift is 6 in one SC-FDMA symbol, Δ_(shift)^(PUCCH)=2 and FF=6 can be paired.

TABLE 18 Multiplexing Frequency order due to Δ_(shift) ^(PUCCH) Factor(FF) circular shift only 1 12 12 2 6 6 3 4 4 4 3 3 6 2 2 12 1 1

Alternatively, the frequency factor can be RRC signaled or implicitlydetermined on the basis of the number of DL CCs. Specifically, thefrequency factor can be implicitly determined on the basis of the numberof configured DL CCs or on the basis of the number of activated DL CCs.For example, a frequency factor for 5 configured (activated) DL CCs canbe configured to 2 in advance and used. Frequency factors for 4, 3, 2and 1 configured (activated) DL CCs can be implicitly configured andused, respectively.

FIG. 43a illustrates a signal processing procedure to transmit controlinformation through multiple antennas. Since the overall flow of thesignal processing procedure shown in FIG. 43a is similar to those ofembodiments 1 and 2, described with reference to FIGS. 29 to 34, thefollowing description is focused on a transmit diversity (TxD) mapper,which is a main difference between the signal processing procedure ofFIG. 43a and the signal processing procedures of FIGS. 29 to 34. The TxDmapper performs resource allocation/MIMO (Multiple Input MultipleOutput) precoding/process for transmitting the control informationthrough multiple antennas (ports).

A description will be given of a scheme of transmitting a PUCCH in aMIMO mode using the TxD mapper. While 2Tx transmit diversity scheme isdescribed in the following embodiment, the embodiment can beequally/similarly applied to an n-Tx transmit diversity scheme. It isassumed that a (quasi) orthogonal resource for control informationtransmission is referred to as resource A and a (quasi) orthogonalresource for RS transmission is referred to as resource B. Logicalindexes of resource A and resource B may be liked with each other. Forexample, if the logical index of resource B is given, the logical indexof resource A can be automatically provided. The logical indexes ofresource A and resource B may be configured through different physicalconfiguration methods. The following two cases are present.

1) Control information can be transmitted through the same PRB at allantennas (ports).

A. The control information can be transmitted through two differentresources A (e.g. a combination of an orthogonal code and a subcarriershift (or offset or index) according to frequency factor). For example,the orthogonal code includes a Walsh code and a DFT code and thefrequency factor can be given as N_(sc)/N_(freq) or the reciprocalthereof. Here, N_(sc) denotes the number of subcarriers in a PRB andN_(freq) denotes the number of subcarriers used for control informationtransmission.

B. An RS can be transmitted through two different resources B (e.g. acombination of a circular shift and a DFT cover) selected for eachantenna (port).

2) The control information can be transmitted through different PRBs forantennas. For example, the control information can be transmittedthrough PRB #4 at antenna (port) 0 and transmitted through PRB #6 atantenna (port) 1.

A. Resources for the control information transmitted through differentantennas (ports) are not particularly limited (i.e. the resources can beequal to and different from each other).

B. Resources for RSs transmitted through different antennas (ports) arenot particularly limited (i.e. the resources can be equal to anddifferent from each other).

In a multi-antenna transmit (e.g. 2Tx transmit) mode, two resources A(e.g. a combination of an orthogonal code and subcarrier position (e.g.shift, offset or index) according to frequency factor) for controlinformation transmission and two resources B (e.g. a combination of acircular shift and a DFT cover) for RS transmission can be defined inadvance or provided through physical control channel (e.g. PDCCH)/RRCsignaling. In this case, signaling for the control information and RScan be individually performed. When resource information for one antenna(port) is signaled, resource information for the other antenna (port)can be inferred from the previously signaled resource information. Forexample, code index m and/or the subcarrier position (e.g. shift, offsetor index) according to frequency factor can be designated in advance orsignaled from the BS. Otherwise, code index m and/or the subcarrierposition (e.g. shift, offset or index) according to frequency factor canbe implicitly linked with a CCE index that consists of a PDCCH. Or, codeindex m and/or the subcarrier position (e.g. shift, offset or index)according to frequency factor can be explicitly designated through PDCCHor RRC signaling. The code index m and/or the subcarrier position (e.g.shift, offset or index) according to frequency factor can be changed ona subframe, slot or multi-SC-FDMA symbol basis. That is, the code indexm and/or the subcarrier position (e.g. shift, offset or index) accordingto frequency factor can be hopped in the unit of a specific timeinterval (e.g. slot).

If the multiplexing order for the RS is more than twice the multiplexingorder for the control information, the following 2Tx transport diversityscheme can be applied. In this case, two from among resources CS+OC+PRBfor the RS may be used for channel estimation of each transmit antennaand only one resource (subcarrier position+OC+PRB) may be used for thecontrol information.

As another transport diversity scheme, the Alamouti scheme can beapplied to an output value of the DFT precoder in the frequency domain.The Alamouti scheme can be represented by the following matrix.

$\begin{matrix}\begin{pmatrix}s_{1} & {- s_{2}^{*}} \\s_{2} & s_{1}^{*}\end{pmatrix} & \left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack\end{matrix}$

Here, column 0 and column 1 respectively denote signal vectorstransmitted through antenna (port) 0 and antenna (port) 1, row 0 and row1 respectively denote complex signal vectors transmitted through firstand second subcarriers, * represents complex conjugate operation. Anyform linearly transformed from the matrix can be applied to the presentinvention.

When the Alamouti scheme is applied to the PUCCH format according to theembodiment of the present invention, the order of DFT symbols mapped toSC-FDMA symbols corresponding to antenna (port) 1 is changed for everytwo DFT symbols. For example, d_0, d_1, d_2, d_3 are mapped to theSC-FDMA symbols corresponding to antenna (port) 0 whereas −d_1*, d_0*,−d_3*, d_2* are mapped to the SC-FDMA symbols corresponding to antenna(port) 1. This damages single carrier property of the signal mapped toantenna (port) 1, and thus CM increases at antenna (port) 1.

A multi-antenna coding scheme that does not cause CM increase even whenthe Alamouti scheme is applied will now be described with reference toFIGS. 43b and 43 c. FIGS. 43b and 43c illustrate the spreadingoperation.

Referring to FIGS. 43b and 43 c, when the control information is mappedto antenna (port) 0, the complex signal is mapped to subcarriers afterbeing subjected to DFT precoding. When the control information is mappedto antenna (port) 1, (1) mapping to subcarriers in SC-FDMA symbols inreverse order, (2) complex conjugate operation and (3) alternative minussign addition are performed. Operations (1), (2) and (3) are exemplaryand the order of the operations can be changed. This scheme can beequally applied to the embodiments of the present invention. Forexample, referring to FIG. 29 or 30, a complex symbol sequence mapped toSC-FDMA symbols transmitted through a first antenna (port) and a secondantenna (port) can be given as follows.

First antenna (port): a_(k)

Second antenna (port): (−1)^(mod(k,2))·conj(a_(11−k))   [Equation 11]

Here, a_(k) denotes the complex symbol sequence mapped to subcarriers ofthe SC-FDMA symbols, k denotes a complex symbol index (0 to 11), mod (a,b) represents the remainder obtained when a is divided by b, and conj(a)represents the complex conjugate value of a.

Equation 12 assumes a case in which the complex signal is mapped to allsubcarriers in the SC-FDMA symbols. Equation 16 can be normalized toEquation 11 considering a case in which the frequency factor is used asshown in FIGS. 31 to 34.

First antenna (port): a_(k)

Second antenna (port): (−1)^(mod(k,2))·conj(a_(n−k))or(−1)^(mod(k+1,2))·conj(a_(n−k))   [Equation 12]

Here, n represents (length of complex symbol sequence a_(k) mapped tothe subcarriers of the SC-FDMA symbols)−1 (e.g. 0≦n≦11).

The complex symbol sequence mapped to the SC-FDMA symbols transmittedthrough the first antenna (port) or the second antenna (port) can becircular-shifted (e.g. shifted by half the length of the complex symbolsequence) in the frequency domain. Tables 19 to 21 show cases in whichthe Alamouti scheme is applied according to the embodiment of thepresent invention.

TABLE 19 SC-FDMA Subcarrier index symbol 0 1 2 3 4 5 6 7 8 9 10 11Antenna a₀  a₁   a₂ a₃  a₄ a₅  a₆ a₇  a₈ a₉   a₁₀ a₁₁  (port) 0 Antenna−a₁₁* a₁₀* −a₉* a₈* −a₇* a₆* −a₅* a₄* −a₃* a₂* −a₁* a₀* (port) 1

TABLE 20 SC-FDMA Subcarrier index symbol 0 1 2 3 4 5 6 7 8 9 10 11Antenna a₀ a₁  a₂ a₃  a₄ a₅  a₆  a₇   a₈ a₉   a₁₀ a₁₁  (port) 0 Antenna−a₅* a₄* −a₃* a₂* −a₁* a₀* −a₁₁* a₁₀* −a₉* a₈* −a₇* a₆* (port) 1

TABLE 21 SC-FDMA Subcarrier index symbol 0 1 2 3 4 5 6 7 8 9 10 11Antenna a₀ a₁  a₂ a₃  a₄ a₅  (port) 0 Antenna −a₅* a₄* −a₃* a₂* −a₁* a₀*(port) 1

Example 3

FIG. 44 illustrates a PUCCH format structure and a signal processingprocedure for the same according to a third embodiment of the presentinvention. Since the overall flow of the signal processing procedure issimilar to those described with reference to FIGS. 29 to 43, thefollowing description is focused on a CAZAC modulator that is a maindifference between the signal processing procedure of FIG. 44 and thesignal processing procedures of FIGS. 29 to 43.

Referring to FIG. 44, the CAZAC modulator modulates the modulatedsymbols [c_0, c_1, . . . , c_L/2−1] and [c_L/2, c_L/2+1, . . . , c_L−1])divided and assigned to corresponding slots into corresponding sequencesto generate CAZAC modulated symbols [d_0, d_1, . . . , d_L/2−1] and[d_L/2, d_L/2+1, . . . , d_L−1]. The CAZAC modulator includes a CAZACsequence or a sequence for LTE computer generated (CG) 1RB. For example,if the LTE CG sequence is r_0, . . . , r_L/2−1, a CAZAC modulated symbolmay be d_n=c_n*r_n or d_n=conj(c_n)*r_n. While FIG. 44 illustratesslot-level joint coding, the present invention can be equally applied toseparate coding for each slot, slot-level repetition, and a case inwhich a frequency factor is applied. In the present embodiment,cell-specific scrambling can be omitted because a CAZAC or CG sequencefunctioning as a base sequence is cell-specific. Otherwise, onlyUE-specific scrambling can be applied for greater randomization. Aresource allocation method, relation with RS indexes, a signalingmethod, and transmit diversity can use the methods described in theabove embodiments.

Example 4

A description will be given of a case in which dynamic ACK/NACK resourceallocation is applied to the new PUCCH formats described in the first,second and third embodiments. The following description can be equallyapplied to other new PUCCH formats as well as the new PUCCH formatsaccording to the present invention. For example, LTE PUCCH format 2 canbe reused as a new PUCCH format for multi-ACK/NACK. In this case,resource indexing for ACK/NACK can employ the method used in LTE PUCCHformat 2, that is, the method of indexing resources on the circularshift axis first, and then indexing PRBs. Use of LTE PUCCH format 2 as anew PUCCH format has the advantage of using an existing format. However,because only up to 13 bits can be supported and a coding rate is limitedin PUCCH format 2, the PUCCH format 2 is inferior to the PUCCH formatsdescribed in the above embodiments in terms of flexibility andperformance.

A region (or PRB) for a new PUCCH format can be defined as follows.

1. An additional PUCCH region (or PRB) for LTE-A can be defined inaddition to the PUCCH region defined in LTE.

2. Part of the PUCCH region (or PRB) defined in LTE can be derived. Thatis, some resources of the PUCCH region can be used as resources for thenew PUCCH format while the PUCCH region is defined according to LTE.

A description will be given of PUCCH format adaptation according to acarrier aggregation scenario. A PUCCH format used for PUCCH formatadaptation is not limited. The PUCCH format adaptation described in thespecification is divided into the following two types.

1. PUCCH format adaptation according to carrier aggregationconfiguration

2. Format adaptation on the basis of the number of PDCCHs and/or PDSCHsallocated to a UE

A. PUCCH format adaptation based only on the number of PDCCHs/PDSCHs

B. Format adaptation based on the number of DL CCs carrying PDCCHs orPDSCHs

As a first PUCCH format adaptation scheme, the format adaptation schemeaccording to carrier aggregation configuration is described. When thenumber (N) of cell-specifically or UE-specifically aggregated DL CCs isless than a specific value (e.g. 2), an ACK/NACK resource may correspondto the lowest CCE index of PDCCH as in LTE. Here, the aggregated DL CCsmay be candidate DL CCs from which a PDCCH is detected for cross-carrierscheduling. Furthermore, the aggregated DL CCs may be some of DL CC setsconfigured for respective cells. Moreover, the aggregated DL CCs may beactivated DL CCs. The PUCCH format used in this case may be the LTEPUCCH format 1/1a/1b. Schemes that can be used when N≧2 includemulti-sequence modulation (MSM) that performs simultaneous transmissionusing M (M≦N) resources and ACK/NACK multiplexing (or sequenceselection) that selects some of resources and transmits using theselected resources. The PUCCH format used in this case may be the LTEPUCCH format 1/1a/1b. When N=1, that is, when carrier aggregation is notperformed (i.e. 1DL-1UL pairing), ACK/NACK resources can use the LTErule and PUCCH format 1/1a/1b intact.

When the number (N) of aggregated DL CCs is equal to or greater than aspecific value (e.g. 2), ACK/NACK can be transmitted through new PUCCHformats described in the first, second and third embodiments. A PUCCHresource can be configured such that it corresponds to the lowest CCEindex regardless of whether a region (or PRB) for a new PUCCH format isdefined exclusively or defined compatibly with LTE. In this case,transmitted multiple ACK/NACK information may correspond to datatransmitted through multiple DL CCs.

As a second PUCCH format adaptation scheme, PUCCH format adaptation onthe basis of the number of PDCCHs and/or PDSCHs assigned to a UE isdescribed. While the number of DL CCs including PDCCHs equals the numberof DL CCs including PDSCHs in non-cross-carrier scheduling, they maybecome different from each other when cross-carrier scheduling isemployed. Furthermore, if the number of PDCCHs or PDSCHs for each DL CCis limited to 1, the number of PDCCHs/PDSCHs may correspond to thenumber of DL CCs used for the PDSCHs. An implicit rule for ACK/NACKresources relate to the PDCCHs. Since the number of PDSCHs equals thenumber of PDCCHs, the following description is made on the basis of thenumber of PDCCHs unless mentioned specifically.

Furthermore, PUCCH format adaptation based on the number of DL CCscarrying PDCCHs/PDSCHs can be achieved by extending PUCCH formatadaptation based on the number of PDCCHs. Here, the PDCCHs may bescheduled PDCCHs. In other words, the PDCCHs may be present in aUE-specific search space. When the number of PDCCHs received through oneDL CC is equal to or less than N, the UE transmits ACK/NACK using LIEPUCCH format 1a/1b. In this case, LTE rule (i.e. implicit resourceallocation based on the lowest CCE index) may be used as a resourceallocation rule. When the number of PDCCHs received through one DL CC isgreater than N, the UE transmits ACK/NACK using a new PUCCH format.Here, for resource allocation, explicit resource allocation can be used(e.g. RRC, PDCCH signaling). If N=1, ACK/NACK information can betransmitted through the same physical channel as that in LTE PUCCHformat 1/1a/1b and a corresponding resource can be determined by thelowest CCE index of PDCCHs. If N=2, ACK/NACK information can betransmitted using multi-sequence modulation (MSM) or channel selectionbased on LTE PUCCH format 1/1a/1b. In this case, resource allocation canconform to LTE rules (i.e. MSM or channel selection is performed usingthe lowest CCE indexes n_cce0 and n-cce1 of PDCCHs). Here, LTE basedPUCCH transmission means not only MSM or channel selection but alsoother modified forms. For example, LTE PUCCH format 1/1a/1b has aspreading factor (SF) of 4. In this case, UE multiplexing or informationquantity can be increased by reducing the SF (e.g., SF=2). The presentinvention also includes this type of the transmission scheme. Inaddition, the present invention includes a scheme of increasing thequantity of information in consideration of both RS and data resourcesduring channel section. If N=3 and the number of PDCCHs detected by theUE is 2, resources can be inferred through the detected PDCCHs andtransmitted. One DL CC carrying the PDCCHs may be a DL Primary CC (DLPCC).

As an another aspect, when a total of N scheduled PDCCHs is transmittedto the UE, ACK/NACK information may be transmitted using LTE resourceallocation rule (implicit resource allocation) and a physical channelbased on LTE PUCCH format 1/1a/1b if DL CCs carrying the N PDCCHsinclude at least one DL PCC. If the N PDCCHs are transmitted through aDL Secondary CC (DL SCC) only, multiple ACK/NACK information can betransmitted using a new PUCCH format. In this case, resource allocationcan conform to explicit resource allocation rules (e.g. RRC signaling orPDCCH signaling).

As a still another aspect, when the number of PDCCHs scheduled to one UEis equal to or less than a specific value (N), resources for ACK/NACKtransmission may conform to LTE rules corresponding to the lowest CCEindex of a PDCCH. In this case, LTE PUCCH format 1/1a/1b can be used.When N≧3, MSM which simultaneously transmits ACK/NACK information usingM (M≦N) resources or ACK/NACK multiplexing (or sequence selection) whichselects some of multiple resources and transmits using the selectedresources can be used. In this case, LTE PUCCH 1/1a/1b can be used. WhenN=1, that is, when only one PDCCH is scheduled for the UE, resources forACK/NACK transmission can use LTE rule and PUCCH format 1/1a/1b intact.

FIG. 45 illustrates PUCCH format adaptation and a blind decodingoperation of the BS according to PUCCH format adaptation in a carrieraggregation system. Considering cross-carrier scheduling (when CIF isconfigured), multiple PDCCHs may be transmitted through one DL CC. Forexample, 2 PDCCHs for PDSCHs that will be transmitted through DL PCC andDL SCC0 can be transmitted through the DL PCC.

Referring to FIG. 45, PDSCH0 is transmitted on DL PCC, and PDCCH0 forthe PDSCH0 is also transmitted on DL PCC. In addition, PDCCH1 for aPDSCH that will be transmitted through DL SCC0 is transmitted on the DLPCC. PDSCH1 is transmitted on DL SCC0. In this case, the UE may detectthe PDCCHs in the following cases.

(1) The UE successfully detects both PDCCH0 and PDCCH1

(2) The UE successfully detects PDCCH0 only.

(3) The UE successfully detects PDCCH1 only.

(4) The UE fails to detect both PDCCH0 and PDCCH1.

It is assumed that ACK/NACK information is fed back using LTE rule andan LTE PUCCH format when the UE detects one PDCCH (or PDSCH), and theACK/NACK information is fed back using a new PUCCH format/rule/resourcewhen the UE detects two or more PDCCHs (or PDSCHs). The UE may transmita PCCH according to a PDCCH detection result as follows.

The UE transmits a PUCCH using the new PUCCH format/rule/resource in thecase of (1) and (4).

The UE transmits a PUCCH using an LTE PUCCH format/rule/resourcecorresponding to PDCCH0 in the case of (2).

The UE transmits a PUCCH using an LTE PUCCH format/rule/resourcecorresponding to PDCCH1 in the case of (3) .

The BS needs to perform blind decoding for the above three cases inorder to successfully receive the PUCCH. Accordingly, the number ofblind decoding operations increases as the number of cross-carrierscheduling scenarios increases.

The present invention additionally proposes schemes for minimizing thenumber of blind decoding operations when cross-carrier scheduling ispermitted. These schemes will be described for a case in which the UEreceives one PDCCH (PDSCH). Here, the UE receiving one PDCCH (PDSCH)means the UE receiving one PDCCH (or PDSCH) irrespective of the numberof PDCCHs (or PDCCHs) that the BS actually transmits.

(Scheme 1) ACK/NACK may be transmitted using the LTE PUCCHformat/rule/resource when one PDCCH is received through DL PCC andnon-cross-carrier scheduling is employed, whereas ACK/NACK may betransmitted using a new PUCCH format/rule/resource in other cases.Non-cross-carrier scheduling includes a case in which a cross-carrierscheduling mode is not configured, a case in which a CIF is notconfigured, and a case in which a CIF indicates self-scheduling. When aPDCCH transmission DL CC (scheduling DL CC) and a PDSCH transmission DLCC (scheduled DL CC) are the same(i.e. in the case of non-cross-carrierscheduling for the corresponding PDSCH) and the number PDCCH (or PDSCH)is one, the DL CC may be assumed as a DL PCC.

(Scheme 2) ACK/NACK may be transmitted using the LTE PUCCHformat/rule/resource when the CIF indicates a DL PCC, and ACK/NACK maybe transmitted using a new PUCCH format/rule/resource in other cases.For example, if the CIF of the DL PCC is 0, the UE can transmit ACK/NACKthrough a UL PCC using the LTE PUCCH format/rule/resource when a PDCCHwith CIF=0 is received through DL SCC0 and a PDSCH is received throughthe DL PCC.

(Scheme 3) A hybrid method of the above two schemes can be used. Forexample, when one PDCCH is received through the DL PCC andnon-cross-carrier scheduling is employed, or when the CIF of a detectedPDCCH indicates the DL PCC, the UE can transmit ACK/NACK through the ULPCC according to the LTE PUCCH format/rule/resource.

FIGS. 46, 47 and 48 illustrate PUCCH format adaptation according to anembodiment of the present invention. FIG. 46 shows a case in whichACK/NACK is fed back using an LTE PUCCH format/rule/resource and FIGS.47 and show a case in which ACK/NACK is fed back using a new PUCCHformat/rule/resource according to an embodiment of the presentinvention. While description of the present embodiment is focused onscheme 1, it can be applied to scheme 2 and scheme 3 (not shown) in asimilar manner.

Referring to FIG. 46, the UE detects one PDCCH through the DL PCC andrecognizes non-cross-carrier scheduling irrespective of the number ofPDCCHs actually transmitted from the BS. Non-cross-carrier schedulingincludes a case in which a cross-carrier scheduling mode is notconfigured, a case in which a CIF is not configured, and a case in whichthe CIF indicates self-scheduling. That is, when one PDCCH is detectedfrom the DL PCC through self-scheduling, the UE can feed back ACK/NACKusing an LTE PUCCH format/rule/resource corresponding to the PDCCH. Forexample, the UE can feed back ACK/NACK using PUCCH format 1/1a/1b and aresource linked to the lowest CCE index from among CCE indexes used forPDCCH transmission.

Referring to FIG. 47, the BS transmits PDCCH0 and PDCCH1 through a DLPCC. PDCCH0 is assigned for PDSCH0 transmitted through the DL PCC.PDCCH1 is assigned for PDSCH0 transmitted through a DL SCC and performscross-carrier scheduling using a CIF. It is assumed that the UEsuccessfully detects PDCCH1 only. In this case, the UE can feed backACK/NACK using a new PUCCH format/rule/resource because the CIFindicates the DL SCC (that is, cross-carrier scheduling) although the UEhas detected PDCCH1 through the DL PCC. For example, the UE can feedback ACK/NACK using a resource provided through the PUCCH format andexplicit signaling (e.g. RRC signaling, PDCCH) illustrated in FIG. 29.

Referring to FIG. 48, the BS transmits PDCCH0 and PDCCH1 through a DLPCC. PDCCH0 is assigned for PDSCH0 transmitted through the DL PCC.PDCCH1 is assigned for PDSCH1 transmitted through a DL SCC and performscross-carrier scheduling using a CIF. It is assumed that the UEsuccessfully detects both PDCCH0 and PDCCH1. In this case, the UE canfeed back ACK/NACK using a new PUCCH format/rule/resource because itreceives multiple PDCCHs irrespective of the DL PCC. For example, the UEcan feed back ACK/NACK using the PUCCH format illustrated in FIG. 29 anda resource given by explicit signaling (e.g. RRC signaling, PDCCH).

A description will be given of error handling. It is assumed that PUCCHformat adaptation is performed according to whether the number ofdetected PDCCHs is 2 or greater. If a scheduler transmits 2 PDCCHs(which may correspond to 2 PDSCHs transmitted through 2 DL CCs, ingeneral) to one UE, the UE may mis-detect that one PDCCH has beenscheduled. In this case, while the BS expects to receive ACK/NACKinformation through a new PUCCH format for two or more PDCCHs, the UEtransmits ACK/NACK information through an LTE PUCCH format since the UEhas detected one PDCCH. The BS recognizes that DTX is generated for theother PDCCH because the BS receives a PUCCH format different from theexpected format.

Recognition of DTX status of the UE by the BS may affect performance inincremental redundancy (IR) based HARQ. When DTX is generated, forexample, because the UE is not aware of the fact that a PDCCH has beentransmitted, the UE cannot store a decoded soft bit result value of aPDSCH corresponding to the PDCCH in a soft buffer. Accordingly, when DTXis generated, it is necessary for the BS not to change a redundancyversion (RV) or to transmit as many system bits as possible in the eventof HARQ retransmission. However, if the BS is not aware of the DTXstatus of the UE and performs retransmission with a different RV value,system throughput may be decreased because the RV is changed and systembits are lost during retransmission. For this reason, since the WCDMAspecification, 3GPP specifies that the DTX status of the UE is signaledto the BS.

A description will be given of PUCCH format adaptation depending on UCIbit size as another aspect of the present invention. In the case of newPUCCH format, it is difficult to use conventional punctured RM codingbecause a coded bit size is different from that of LTE. As a solution tothis, tail-biting convolutional coding (TBCC) defined in LTE can be usedfor the new PUCCH format. However, due to characteristic of TBCC,channel coding performance for information bit sizes smaller than(constraint length)-1 cannot be ensured and the currently defined schemefor TBCC cannot be used without being modified. For example, becauseTBCC of LTE has a constraint length of 7, zero-padding can be performedfor information having less than 6 bits until the information becomes 6bits, or a channel coding input size. Accordingly, the present inventionproposes a scheme of using LTE PUCCH format 1/1a/1b for transmission(including LTE PUCCH format transmission, MSM and channel selection) ofUCI having less than M bits and using a new PUCCH format employing TBCCfor UCI having M bits or more. The value M can be determined such thatit corresponds to a constraint length. For example, M=K−1 (K being theconstraint length). When K=7, M may be 6. When M=K−2, for example,channel selection used in LTE TDD is employed for an information bitsize of 4 or less. In the case of an information bit size of 5, onearbitrary bit (e.g. bit 0) can be padded to generate 6 bits and a newPUCCH format employing TBCC can be used. For an information bit size ofgreater than 6 bits, a new PUCCH format using TBCC can be employed.

Alternatively, it is possible to adaptively use LTE format 2 or a newPUCCH format depending on the number of configured DL CCs, the number ofactivated DL CCs, the number of scheduled DL grants (or PDSCHs), or theinformation bit size. For example, LTE PUCCH format 2 can be used whenthe number of configured DL CCs is M1 or less, the number of activatedDL CCs is M2 or less, the number of scheduled DL grants (or PDSCHs) (orthe number of DL CCs carrying a allocated DL grant) is M3 or less, orthe information bit size is M4 or less, whereas a new PUCCH format canbe used when the number of configured DL CCs is greater than M1, thenumber of activated DL CCs is greater than M2, the number of scheduledDL grants (or PDSCHs) (or the number of DL CCs carrying a allocated DLgrant) is greater than M3, or the information bit size is greater thanM4. For example, LTE PUCCH format 2 can be used when the information bitsize is M4 or less, otherwise the DFT-based PUCCH format illustrated inFIG. 29 can be used as a new PUCCH format. A channel coding scheme usedfor the new PUCCH format may be (32,0) RM coding or TBCC. When TBCC isused as the channel coding scheme for the new PUCCH format, M1, M2, M3and M4 may be related to the constraint length (K) of TBCC. A value ofK−1 relates to a memory size of TBCC. TBCC cannot ensure performance forinformation bit sizes of less than K−1 while ensuring the performancefor information bit sizes of K−1 or greater. For example, when K=7, anew PUCCH format employing TBCC can be used for a payload of 6 bits ormore whereas PUCCH format 2 using punctured RM coding defined in LTE canbe used for a payload of less than 6 bits.

FIG. 49 shows a block error rate according to PUCCH format when UCI is5-bit information, FIG. 50 shows a block error rate according to PUCCHformat when UCI is 6-bit information, and FIG. 51 shows a block errorrate according to PUCCH format when UCI is 12-bit information. The PUCCHformat shown in FIG. 29 is used as a new PUCCH format. The constraintlength (K) of DFT based TBCC is 7. Referring to FIGS. 49, 50 and 51, LTEPUCCH format 2 is superior to other PUCCH formats for information bitsizes less than K−1 (that is, 6 bits) and the DFT-based PUCCH formatusing TBCC is superior to other PUCCH formats for information bit sizesK−1 or greater. For convenience of description, while LTE PUCCH format 2using punctured RM and DFT-based PUCCH format using TBCC are comparedwith each other, the present invention is not limited to thereto. Thatis, coding schemes other than those described herein can be adaptivelyapplied to PUCCH formats depending on information bit size.

The present invention can be equally applied to adaptive use of LTEPUCCH format 2 or a new PUCCH format depending on the number ofconfigured DL CCs, the number of activated DL CCs or the number ofallocated DL grants (or the number of DL CCs carrying allocated DLgrants). For example, it is necessary to support 5-bit information, ifeach of two DL CCs needs to transmit two codewords (5²−1 states areneeded). Accordingly, ACK/NACK for two or less DL CCs (or two activatedDL CCs or two allocated PDCCHs) is transmitted using LTE PUCCH format 2and ACK/NACK for more than two DL CCs is transmitted using a new PUCCHformat.

Alternatively, it is necessary to support 5-bit information, if each ofthree DL CCs needs to transmit one codeword (3³−1 states are needed).Accordingly, ACK/NACK for three or less DL CCs (or three activated DLCCs or three allocated PDCCHs) is transmitted using LTE PUCCH format 2and ACK/NACK for more than three DL CCs is transmitted using a new PUCCHformat.

A description will be given of a resource determination method forACK/NACK and a DTX handing method in a new PUCCH format. Here, it isassumed that the new PUCCH format can simultaneously transmit ACK/NACKinformation corresponding to multiple DL CCs and information includingDTX statuses of DL CCs. For example, if 5 DL CCs are present and each DLCC transmits 2 codewords, the new PUCCH format can carry at least 12-bitinformation for supporting ACK/NACK and DTX for the 5 DL CCs.

While a case in which PUCCH resources for the new PUCCH format areexclusively reserved for each CC and a case in which at least some of aplurality of CCs are shared are described for facilitation ofexplanation, the present invention is not limited thereto. If 4 DL CCsare present and 10 PUCCH resources are reserved for each DL CC as anexample of exclusive reservation of resources for PUCCH transmission foreach CC, 40 (=10*4) PUCCH resources can be reserved, PUCCH resourceindexes 0 to 9 can be used for DL CC #0, PUCCH resource indexes 10 to 19can be used for DL CC #1, PUCCH resource indexes 20 to 29 can be usedfor DL CC #2, and PUCCH resource indexes 30 to 39 can be used for DL CC#3 (PUCCH resource stacking). If 4 DL CCs are present and 10 PUCCHresources are reserved for each DL CC as an example of sharing PUCCHresources by multiple CCs, PUCCH resource indexes 0 to 9 can be sharedfor all DL CCs.

As described above, a PUCCH region (or PRB) in which the new PUCCHformat can be used can be defined as a new region (or a specific sectionof resources) for LTE-A or defined using some resources defined in LTE.Furthermore, “lowest CCE” concept can be used as in LTE or anotherimplicit method can be applied.

Examples of detailed resource allocation according to the presentinvention will now be described.

A case in which resources are stacked and defined for DL CCs isdescribed as a first example. DL CCs may include the above-mentioned CCs(e.g. configured DL CCs, activated DL CCs, DL CCs including scheduledPDCCHs, etc.)

It is assumed that 4 ACK/NACK signals need to be transmitted for 4PDSCHs transmitted through 4 DL CCs and the ACK/NACK signals aretransmitted through one UL CC (e.g. anchor UL carrier). Here, ACK/NACKincludes ACK, NACK, DTX and NACK/DTX. It is assumed that 10 PUCCHresources are reserved for each DL CC such that a total of 40 PUCCHresources are reserved. While the present embodiment is described forone UE (i.e. UE #0), it can be equally applied to multiple UEs.Furthermore, while the present embodiment describes sequential indexingof resources 0 to 39 in exclusive resource definition, it can also beapplied to a case in which 4 PUCCH resource regions each having indexes0 to 9 for each DL CCs are present.

FIG. 52 illustrates an example of transmitting multiple PDCCHs inassociation with a downlink assignment carrier index (DACI) at UE #0. Inthis case, statuses of all DL CCs for PDSCHs are transmitted accordingto the new PUCCH format, and thus it is difficult to apply CCE basedimplicit mapping of LTE. In the present embodiment, it is assumed thatone PDCCH is transmitted to UE #0 for each CC, UE #0 successfullydecodes all PDCCHs to generate no DTX, and CCE indexing in each DL CCstarts from 0. Furthermore, CCE indexing can include CCE indexing ofprevious DL CCs. For example, CCE indexes for DL CC #1 may be 10 to 19.

A DACI is a counter for PDCCHs transmitted to a UE and is configured foreach UE. When a plurality of PDCCHs is transmitted, the DACI canindicate the order of the PDCCHs. If 4 PDCCHs are transmitted, as shownin FIG. 45, the DACI has values of 0 to 3. The DACI may be included in aDCI field of the corresponding PDCCHs and signaled to the correspondingUE, or signaled to the UE through other signaling methods. A downlinkassignment index (DAI) field used in LTE TDD can be used as a DACIfield.

The DACI can indicate the number of PDSCHs (or the number of PDCCHs) inall DL CCs. For example, if the DACI indicates the number of PDCCHs inthe example shown in FIG. 45, all the DACI values in the PDCCHs may be4. When the DACI indicates the number of PDCCHs, the DACI can be appliedto a case in which the UE transmits ACK/NACK in an ACK/NACK bundlingmode. ACK/NACK bundling is a method of transmitting representativeACK/NACK through a logical AND operation. For example, NACK istransmitted as a representative value when at least one of ACK/NACKresults corresponds to NACK and ACK is transmitted as a representativevalue when all the ACK/NACK results correspond to ACK. If the number ofPDCCHs successfully decoded by the UE is 3 although a DACI valueindicating the total number of PDCCHs is 4, which means that one PDCCHis not decoded, NACK, DTX or NACK/DTX can be signaled as arepresentative value to the BS. Accordingly, the BS and the UE can beaware of a DTX status using the DACI. The method of transmitting NACKwhen DTX is generated is exemplary and a DTX status may be signaled bytransmitting no information. The present invention is not limited by theDTX signaling scheme.

For facilitation of description, a case in which the DACI is used as aCC index counter is described. A DACI counter can be set such that itcorresponds to a carrier indicator field (CIF) for cross-carrierscheduling. For example, if a CIF value is 3 bits, a DACI value may alsobe 3 bits.

The DACI may be counted from a low frequency CC to a high frequency CC(or counted from a high frequency CC to a low frequency CC). Otherwise,the DACI may be circularly counted in ascending order from the primarycarrier. If multiple PDCCHs are transmitted in one DL CC, the DACI canbe counted from a low CCE index to a high CCE index. For example, whenthe lowest CCE index of PDCCH0 in DL CC #0 for a PDSCH of DL CC #1 is 10and the lowest CCE index of PDCCH1 in DL CC #0 for a PDSCH of DL CC #2is 20, PDCCH0 may have a DACI value lower than that of PDCCH1.Alternatively, a DACI value transmitted in each PDCCH may be determinedby the network without a particular rule and transmitted. That is, theDACI may not conform to a specific rule.

The DACI may be defined as a combination with a DAI used in LTE TDD. Forexample, when 4 DAI statuses and 5 DACI statuses are present, a total of20 combinations of DAI and DACI can be defined with indexes of 0 to 19.Even in this case, the present invention is applicable.

A primary objective of the DACI is to enable the UE to detect DTX. Forexample, if decoding of a PDCCH corresponding to DL CC #2 fails in theexample of FIG. 45, UE #0 acquires DACI counter values 0, 1 and 3through DCI0, DCI1 and DCI3, respectively. UE #0 may recognize thatblind decoding of DCI2 has failed (i.e. enters a DTX status) becauseDACI=2 is missed and transmit the DTX status to the BS.

However, even when the DACI is used, UE #0 cannot be aware of whether ornot blind decoding of the last DCI fails. In other words, when UE #0fails to decode the last DCI even though the BS has transmitted the lastDCI to UE #0, UE #0 cannot be aware of whether decoding of the last DCIfails or the BS does not transmit the last DCI. Referring to FIG. 52,when UE #0 fails to decode DCI3 although the BS has transmitted DCI3 inDL CC #3, UE #0 does not know whether DCI3 is present or decoding ofDCI3 fails.

Therefore, the present embodiment proposes a method for correctlyproviding ACK/NACK (including DTX) states for all DL PDSCHs to the BSand UEs. Specifically, the present embodiment proposes a method oftransmitting ACK/NACK information using a PUCCH resource correspondingto a PDCCH over which the last value of the DACI counter is transmitted.

FIG. 53 illustrates an embodiment according to the present invention.This embodiment shows a case in which the BS transmits 4 PDCCHs and UE#0 successfully decodes all PDCCHs. In this case, ACK/NACK informationfor 4 PDSCHs transmitted through 4 DL CCs is delivered through PUCCHresource 34 corresponding to the lowest CCE index 4 of a PDCCH havingthe largest DACI value 3 from among the detected PDCCHs. If the DACI iscounted in reverse order (e.g. 3, 2, 1, 0), the ACK/NACK information canbe transmitted through PUCCH resource 2 corresponding to the lowest CCEindex 2 of the first PDCCH (DL CC #0).

FIG. 54 illustrates a case in which UE #0 successfully decodes a PDCCHcorresponding to DCI2 and fails to decode a PDCCH corresponding to DCI3.The BS will expect to receive ACK/NACK information through PUCCHresource 34 from UE #0 on the assumption that UE #0 successfully decodesDCI3. However, when UE #0 successfully decodes DCI2 (it is not necessaryto consider whether or not DCI0 and DCI1 are successfully decodedbecause UE #0 can recognize it through DACI) but fails to decode DCI3,UE #0 transmits the ACK/NACK information through PUCCH resource 20corresponding to DCI2. Accordingly, the BS can recognize whether DTX wasoccurred as for the last DCI3 through the transmitted resource.

FIG. 55 illustrates a case in which UE #0 fails to decode DCI0, DCI2 andDCI3. UE #0 can recognize whether decoding of DCI0 fails through areceived DACI because UE #0 has successfully decoded DCI1. However, UE#0 cannot be aware of whether DTX is generated for DCI2 and DCI3. UE #0transmits ACK/NACK information through PUCCH resource 16 correspondingto the lowest CCE index 6 of a PDCCH having the largest DACI value 1from among detected PDCCHs although UE #0 does not know whether DTX isgenerated for DCI2 and DCI3. Accordingly, the BS can recognize that DTXis generated for DCI2 and DCI3.

FIG. 56 illustrates a case in which 2 PDCCHs are transmitted through DLCC #3 on the assumption that the DACI is counted from a low CCE index toa high CCE index when a plurality of PDCCHs is transmitted through oneDL CC. In this case, UE #0 transmits ACK/NACK information through PUCCHresource 36 corresponding to the lowest CCE index 6 of a PDCCH havingthe largest DACI value 3 from among detected PDCCHs.

FIG. 57 illustrates a case in which 2 PDCCHs are transmitted through DLCC #3 and a DCI having a lower CCE index has a larger DACI value. Inthis case, UE #0 transmits ACK/NACK information through PUCCH resource34 corresponding to the lowest CCE index 4 of a PDCCH having the largestDACI value 3 from among detected PDCCHs.

A description will be given of a case in which PUCCHs for DL CCs aredefined such that the PUCCHs are shared with reference to FIGS. 58, 59and 60.

FIG. 58 illustrates a case in which UE #0 successfully decodes all 4PDCCHs for DL CCs while the PDCCHs are shared. In this case, UE #0transmits ACK/NACK information through PUCCH resource 4 corresponding tothe lowest CCE index 4 of a PDCCH having the largest DACI value 3 fromamong the detected PDCCHs.

FIG. 59 illustrates a case in which UE #0 fails to decode DCI3 withDACI=3. In this case, UE #0 transmits ACK/NACK information through PUCCHresource 0 corresponding to the lowest CCE index 0 of a PDCCH having thelargest DACI value 2 from among the detected PDCCHs. Accordingly, the BScan recognize that DTX is generated for DCI3.

FIG. 60 illustrates a case in which PUCCH resources for DL CCs partiallyoverlap. UE #0 transmits ACK/NACK information in the same manner as theabove cases.

Another scheme for solving a DTX problem for the last DACI value willnow be described. Specifically, a scheme of simultaneously using aparameter indicating a PDCCH counter value and a parameter indicatingthe number of PDCCHs is proposed.

For example, if DACI0 serves as a PDCCH counter (e.g. DACI counts 0 to 7when it is 3 bits), DACI1 can transmit information indicating the numberof allocated PDCCHs (or PDSCHs) (e.g. DACI transmits 1 to 8 when it is 3bits; 0 need not be transmitted). For example, when 4 PDCCHs aretransmitted, each PDCCH may carry the following information.

-   -   DCI0: DACI0=0, DACI1=4    -   DCII: DACI0=1, DACI1=4    -   DCI2: DACI0=2, DACI1=4    -   DCI3: DACI0=3, DACI1=4

Here, DACI1 can be additionally defined with DACI0. Alternatively, DACI1may be transmitted over one or more of the PDCCHs. Alternatively, if oneof DCIs is limited such that cross-carrier scheduling is not permittedtherefor, the CIF field of the corresponding DCI can be used to carryDACI1. Alternatively, DACI0 and DACI1 can be transmitted through RRCsignaling or broadcasting signaling.

Another method for solving the DTX problem in the last DACI value usesRRC signaling. In this method, a specific UE can be assigned a uniquePUCCH resource through RRC signaling. The PUCCH resource may be aresource shared by multiple UEs or a resource allocated for SPS orACK/NACK repetition. When DTX is generated in at least one PDCCH, thespecific UE transmits ACK/NACK information through the PUCCH resourceassigned thereto through RRC signaling. When no DTX is generated, the UEperforms dynamic ACK/NACK operation in an implicit manner. Conversely,the UE may transmit the ACK/NACK information using the PUCCH resourceallocated thereto when no DTX is generated and may implicitly performthe dynamic ACK/NACK operation when DTX is generated. In this case, theDACI may simply indicate the number of transmitted PDCCHs. When the DACIindicates the number of transmitted PDCCHs, it is impossible to knowwhich PDCCH is lost and only whether or not DTX is generated can berecognized. The implicit rule for the dynamic ACK/NACK operation is totransmit HARQ-ACK/NACK information using a PUCCH resource correspondingto the lowest CCE index of a PDCCH having the largest CCE index amongPDCCH(s) of the largest CC index, a PUCCH resource corresponding to thelowest CCE index of a PDCCH having the lowest CCE index among PDCCH(s)of the largest CC index, a PUCCH resource corresponding to the lowestCCE index of a PDCCH having the lowest CCE index, among PDCCH(s) of thelowest CC index, or a PUCCH resource corresponding to the lowest CCEindex of a PDCCH having the largest CCE index among PDCCH(s) of thelowest CC index.

If the DACI is defined as a counter, it is possible to perform implicitmapping using the lowest CCE index of a PDCCH having the largest DACIvalue.

FIG. 61 illustrates a case in which a PUCCH resource is defined by thelowest CCE index of a PDCCH having the lowest CCE index among PDCCH(s)of the largest CC index, according to the implicit rule and DTX is notgenerated for any PDCCH. Since DTX is not generated, UE #0 transmitsACK/NACK information through PUCCH resource 34 corresponding to thelowest CCE index 4 of a PDCCH having the largest DACI value 3 from amongdetected PDCCHs. The ACK/NACK information may be information bundled forcontrol information of all PDSCHs.

FIG. 62 illustrates a case in which DTX is generated for DCI1. In thiscase, UE #0 recognizes that DTX is generated for a DCI corresponding toDACI=2 because UE #0 has successfully performed decoding for DACI=0,DACI=1 and DACI=3. UE #0 transmits ACK/NACK information throughRRC-signaled PUCCH resource 100 because DTX has been generated. TheACK/NACK information may be information bundled for control informationof all PDSCHs.

FIG. 63 illustrates a case in which UE #0 fails to decode a PDCCH havingthe last DACI value. In this case, UE #0 cannot be aware of whether DTXis generated for a DCI corresponding to DACI=3. Accordingly, UE #0recognizes that DTX is not generated and transmits ACK/NACK informationthrough PUCCH resource 36 corresponding to the lowest CCE index 6 of aPDCCH having the largest DACI value 2 from among detected PDCCHs. The BSexpects to receive ACK/NACK information (combined ACK/NACK) throughPUCCH resource 34 corresponding to DCI2, which corresponds to the PDCCHhaving the largest DACI value, or RRC-signaled PUCCH resource 100.However, UE #0 transmits the ACK/NACK information through PUCCH resource36 corresponding to DCI3, and thus the BS recognizes that DTX isgenerated for DCI2.

The above-mentioned methods may be combined. For example, the formatadaptation and the schemes for detecting DTX (i.e. the scheme of usingthe CCE index of the PDCCH carrying the last DACI value, the scheme ofsimultaneously transmitting DACI0 and DACI1, and the scheme of using RRCsignaling) can be combined.

FIG. 64 is a block diagram showing configurations of a BS and a UE.

Referring to FIG. 64, a wireless communication system includes a BS 110and a UE 120. The BS includes a processor 112, a memory 114, an RF unit116. The processor 112 may be configured to implement the proceduresand/or methods proposed by the present invention. The memory 114 isconnected to the processor 112 and stores information related tooperations of the processor 112. The RF unit 116 is connected to theprocessor 112, transmits and/or receives an RF signal. The UE 120includes a processor 122, a memory 124, and an RF unit 126. Theprocessor 112 may be configured to implement the procedures and/ormethods proposed by the present invention. The memory 124 is connectedto the processor 122 and stores information related to operations of theprocessor 122. The RF unit 126 is connected to the processor 122,transmits and/or receives an RF signal. The BS 110 and/or UE 120 mayinclude a single antenna or multiple antennas.

The embodiments of the present invention described hereinbelow arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It will beobvious to those skilled in the art that claims that are not explicitlycited in each other in the appended claims may be presented incombination as an embodiment of the present invention or included as anew claim by a subsequent amendment after the application is filed.

In the embodiments of the present invention, a description is madecentering on a data transmission and reception relationship among a BS,a relay, and an MS. In some cases, a specific operation described asperformed by the BS may be performed by an upper node of the BS. Namely,it is apparent that, in a network comprised of a plurality of networknodes including a BS, various operations performed for communicationwith an MS may be performed by the BS, or network nodes other than theBS. The term ‘BS’ may be replaced with the term ‘fixed station’, ‘NodeB’, ‘enhanced Node B (eNode B or eNB)’, ‘access point’, etc. The term‘UE’ may be replaced with the term ‘Mobile Station (MS)’, ‘MobileSubscriber Station (MSS)’, ‘mobile terminal’, etc.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the methods according to theembodiments of the present invention may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, the embodiments of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. For example, software code may be stored in a memory unitand executed by a processor. The memory unit is located at the interioror exterior of the processor and may transmit and receive data to andfrom the processor via various known means.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of theinvention should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

INDUSTRIAL APPLICABILITY

The present invention can be used for a UE, a BS or other devices in awireless communication system. Specifically, the present invention isapplicable to a method for transmitting uplink control information andan apparatus therefor.

1-6. (canceled)
 7. A method for, at a user equipment (UE), transmittingAcknowledgement/Negative ACK (ACK/NACK) in a wireless communication thatsupports carrier aggregation, the method comprising: receiving aphysical downlink control channel (PDCCH); receiving a physical downlinkshared channel (PDSCH) indicated by the PDCCH; and transmitting ACK/NACKfor the PDSCH through a physical uplink control channel (PUCCH), whereina PUCCH format for transmitting the ACK/NACK is configured inconsideration of a number of aggregated carriers, wherein if a firstPUCCH format is used for transmitting the ACK/NACK, the number ofaggregated carriers is 1, and if a second PUCCH format is used fortransmitting the ACK/NACK, the number of aggregated carriers is 3 orgreater, and wherein the first PUCCH format uses a sequence generated bya root sequence and a cyclic shift for transmitting the ACK/NACK, andthe second PUCCH format uses discrete Fourier transform (DFT) fortransmitting the ACK/NACK.
 8. The method of claim 7, wherein a resourcefor the first PUCCH format is determined based on an index of a controlchannel element (CCE) that constitutes the PDCCH, and a resource for thesecond PUCCH format is indicated by the PDCCH.
 9. The method of claim 8,wherein the resource for the second PUCCH format is indicated by a valueof a transmit power control (TPC) filed of the PDCCH.
 10. A userequipment (UE) configured to transmit Acknowledgement/Negative ACK(ACK/NACK) in a wireless communication system that supports carrieraggregation, the UE comprising: an radio frequency (RF) unit; and aprocessor, the processor configured to receive a physical downlinkcontrol channel (PDCCH), to receive a physical downlink shared channel(PDSCH) indicated by the PDCCH, and to transmit ACK/NACK for the PDSCHthrough a physical uplink control channel (PUCCH), wherein a PUCCHformat for transmitting the ACK/NACK is configured in consideration of anumber of aggregated carriers, wherein if a first PUCCH format is usedfor transmitting the ACK/NACK, the number of aggregated carriers is 1,and if a second PUCCH format is used for transmitting the ACK/NACK, thenumber of aggregated carriers is 3 or greater, and wherein the firstPUCCH format uses a sequence generated by a root sequence and a cyclicshift for transmitting the ACK/NACK, and the second PUCCH format usesdiscrete Fourier transform (DFT) for transmitting the ACK/NACK.
 11. TheUE of claim 10, wherein a resource for the first PUCCH format isdetermined based on an index of a control channel element (CCE) thatconstitutes the PDCCH, and a resource for the second PUCCH format isindicated by the PDCCH.
 12. The UE of claim 11, wherein the resource forthe second PUCCH format is indicated by a value of a transmit powercontrol (TPC) filed of the PDCCH.
 13. A method for, at a base station(BS), receiving Acknowledgement/Negative ACK (ACK/NACK) in a wirelesscommunication that supports carrier aggregation, the method comprising:transmitting a physical downlink control channel (PDCCH); transmitting aphysical downlink shared channel (PDSCH) indicated by the PDCCH; andreceiving ACK/NACK for the PDSCH through a physical uplink controlchannel (PUCCH), wherein a PUCCH format for receiving the ACK/NACK isconfigured in consideration of a number of aggregated carriers, whereinif a first PUCCH format is used for receiving the ACK/NACK, the numberof aggregated carriers is 1, and if a second PUCCH format is used forreceiving the ACK/NACK, the number of aggregated carriers is 3 orgreater, and wherein the first PUCCH format uses a sequence generated bya root sequence and a cyclic shift for receiving the ACK/NACK, and thesecond PUCCH format uses discrete Fourier transform (DFT) for receivingthe ACK/NACK.
 14. The method of claim 13, wherein a resource for thefirst PUCCH format is determined based on an index of a control channelelement (CCE) that constitutes the PDCCH, and a resource for the secondPUCCH format is indicated by the PDCCH.
 15. The method of claim 14,wherein the resource for the second PUCCH format is indicated by a valueof a transmit power control (TPC) filed of the PDCCH.
 16. A base station(BS) configured to transmit Acknowledgement/Negative ACK (ACK/NACK) in awireless communication system that supports carrier aggregation, the UEcomprising: an radio frequency (RF) unit; and a processor, the processorconfigured to transmit a physical downlink control channel (PDCCH), totransmit a physical downlink shared channel (PDSCH) indicated by thePDCCH, and to receive ACK/NACK for the PDSCH through a physical uplinkcontrol channel (PUCCH), wherein a PUCCH format for receiving theACK/NACK is configured in consideration of a number of aggregatedcarriers, wherein if a first PUCCH format is used for receiving theACK/NACK, the number of aggregated carriers is 1, and if a second PUCCHformat is used for receiving the ACK/NACK, the number of aggregatedcarriers is 3 or greater, and wherein the first PUCCH format uses asequence generated by a root sequence and a cyclic shift for receivingthe ACK/NACK, and the second PUCCH format uses discrete Fouriertransform (DFT) for receiving the ACK/NACK.
 17. The BS of claim 16,wherein a resource for the first PUCCH format is determined based on anindex of a control channel element (CCE) that constitutes the PDCCH, anda resource for the second PUCCH format is indicated by the PDCCH. 18.The BS of claim 17, wherein the resource for the second PUCCH format isindicated by a value of a transmit power control (TPC) filed of thePDCCH.